Abstract: A method for optical isolation in a clear mold package is provided. The method comprises forming a substrate and mounting a first component on the substrate. The method also comprises depositing a clear layer over the first component and the substrate and fabricating a trench in the clear layer near the first component, wherein the trench extends from a top surface of the substrate to the top surface of the clear layer. Further, the method comprises depositing an opaque material within the trench.

Abstract: An electronic package 100 comprising a semiconductor device 105, a heat spreader layer 110, and a thermal interface material layer 115 located between the semiconductor device and the heat spreader layer. The thermal interface material layer includes a resin layer 120 having heat conductive particles 125 suspended therein. A portion of the particles are exposed on at least one non-planar surface 135 of the resin layer such that the portion of exposed particles 130 occupies a majority of a total area of a horizontal plane 140 of the non-planar surface.

Abstract: An optoelectronic semiconductor chip including a radiation passage area, where a contact metallization is applied to the radiation passage area, and a first reflective layer sequence is applied to that surface of the contact metallization which is remote from the radiation passage area, and an optoelectronic component that includes such a chip.

Abstract: An imaging device formed as an active pixel array combining a CMOS fabrication process and a nanowire fabrication process. The pixels in the array may include a single or multiple photogates surrounding the nanowire. The photogates control the potential profile in the nanowire, allowing accumulation of photo-generated charges in the nanowire and transfer of the charges for signal readout. Each pixel may also include a readout circuit which may include a reset transistor, a charge transfer switch transistor, source follower amplifier, and pixel select transistor. A nanowire is generally structured as a vertical rod on the bulk semiconductor substrate to receive the light energy impinging onto the tip of the nanowire. The nanowire may be configured to function as either a photodetector or a waveguide configured to guild the light beam to the bulk substrate. In the embodiments herein, with the presence of the nanowire photogate and a substrate photogate, light of different wavelengths can be detected.

Abstract: An organic light emitting display device. The organic light emitting display device includes a substrate having a pixel region in which pixels are formed and a non-pixel region in which a light sensor is formed, an insulating film formed on the substrate, a first electrode formed on the insulating film and formed of a reflective material reflecting light, the first electrode being formed on the entire surface of the insulating film except for a region between the pixels and a region over the light sensor, a pixel defining film exposing a region of the first electrode and formed on the insulating film, an organic light emitting layer formed on the exposed region of the first electrode, and a second electrode formed on the organic light emitting layer. The first electrode is formed to have a greater area than that of the organic light emitting layer.

Abstract: A photodetector 1 according to an embodiment of the present invention includes: an n-type InAs substrate 12; an n-type InAs buffer layer 14 formed on the n-type InAs substrate 12; an n-type InAs light absorbing layer 16 formed on the n-type InAs buffer layer 14; an InAsXPYSb1-X-Y cap layer 18 (X?0, Y>0) formed on the n-type InAs light absorbing layer 16; a first inorganic insulating film 20 formed on the cap layer 18, and having an opening portion 20h in a deposition direction; a p-type impurity semiconductor region 24 fowled by diffusing a p-type impurity from the opening portion 20h of the first inorganic insulating film 20, and reaching from the cap layer 18 to an upper layer of the n-type InAs light absorbing layer 16; and a second inorganic insulating film 22 formed on the first inorganic insulating film 20 and on the p-type impurity semiconductor region 24.

Abstract: A photodiode device and methods of manufacturing the same are provided. The photodiode device comprises a light absorption layer defining a light-facing side and a back-light side; a via passing through the absorption layer, the via defining a side wall and a bottom surface; a conformal isolation layer covering the side wall and the bottom surface; a first patterned conductive layer disposed on the back-light side, the first patterned conductive layer having a first portion covering a first portion of the conformation isolation layer; a second patterned conductive layer disposed on the light-facing side of the absorption layer; and an opening through the conformal isolation layer, wherein the opening is filled with the second patterned conductive layer such that the second patterned conductive layer is connected with the first portion of the first patterned conductive layer.

Abstract: Provided are a photodetector capable of suppressing variations in the output characteristics among photodiodes, and a display device provided with the photodetector. A display device in use has an active matrix substrate (20) including a transparency base substrate (2), a plurality of active elements and a photodetector. The photodetector includes a light-shielding layer (3) provided on one main surface of the base substrate (2), a photodiode (1) arranged on an upper layer of the light-shielding layer (3), and an electrode (12) arranged in the vicinity of the photodiode (1) on the upper layer of the light-shielding layer (3). The photodiode (1) includes a silicon layer (11), and the silicon layer (11) is insulated electrically from the light-shielding layer (3). The electrode (12) is insulated electrically from the light-shielding layer (3) and the silicon layer (11).

Abstract: Apparatuses capable of and techniques for detecting the visible light spectrum are provided.

Abstract: The semiconductor light receiving element 1 includes a semiconductor substrate 101, and a semiconductor layer having a photo-absorption layer 105 disposed on the top of the semiconductor substrate 101. The semiconductor layer of the semiconductor light receiving element 1 containing at least the photo-absorption layer 105 has a mesa structure, and a side wall of the mesa is provided with a protective film 113 covering the side wall. The protective film 113 is a silicon nitride film containing hydrogen, and a hydrogen concentration in one surface of the protective film 113 located at the side of the mesa side wall is lower than a hydrogen concentration in the other surface of the protective film 113 located at the side that is opposite to the side of the mesa side wall.

Abstract: A tamper-resistant semiconductor device (5;20;30;40;50;60) which includes a plurality of electronic circuits formed on a circuitry side (6) of a substrate (7) having an opposite side which is a backside (8) of the semiconductor device, and comprises at least one light-emitting device (9a-f;21) and at least one light-sensing device (10a-f;22a-b) provided on the circuitry side (6) of the semiconductor device. The light-emitting device (9a-f;21) is arranged to emit light, including a wavelength range for which the substrate (7) is transparent, into the substrate towards the backside (8), and the light-sensing device (10a-f;22a-b) is arranged to sense at least a fraction of the emitted light following passage through the substrate (7) and reflection at the backside (8), and configured to output a signal indicative of a reflecting state of the backside, thereby enabling detection of an attempt to tamper with the backside (8) of the semiconductor device (5;20;30;40;50;60).

Abstract: Disclosed are embodiments of a multi-chip assembly including optically coupled die. The multi-chip assembly may include two opposing substrates, and a number of die are mounted on each of the substrates. At least one die on one of the substrates is in optical communication with at least one opposing die on the other substrate. Other embodiments are described and claimed.

Abstract: The invention relates to a light emitting diode having at least one (semi)conductive electroluminescent active layer which comprises at least two different electroluminescent functionalities, wherein the emission spectrum of the diode exhibits at least two intensity maxima. The invention further relates to a detector which comprises a light emitting diode which is capable of emitting light at least two mutually separate intensity maxima.

Abstract: A hetero-crystalline semiconductor device and a method of making the same include a non-single crystalline semiconductor layer and a nanostructure layer that comprises a single crystalline semiconductor nanostructure integral to a crystallite of the non-single crystalline semiconductor layer.

Abstract: Re-emitting semiconductor constructions (RSCs) for use with LEDs, and related devices, systems, and methods are disclosed. A method of fabrication includes providing a semiconductor substrate, forming on a first side of the substrate a semiconductor layer stack, attaching a carrier window to the stack, and removing the substrate after the attaching step. The stack includes an active region adapted to convert light at a first wavelength ?1 to visible light at a second wavelength ?2, the active region including at least a first potential well. The attaching step is carried out such that the stack is disposed between the substrate and the carrier window, which is transparent to the second wavelength ?2. The carrier window may also have a lateral dimension greater than that of the stack. The removal step is carried out so as to provide an RSC carrier device that includes the carrier window and the stack.

Abstract: A lighting device including an electroluminescent (EL) material is connected to an external power supply easily and the convenience is improved. In a lighting device having a light-emitting element including an electroluminescence (EL) layer, a housing including a light-emitting element has a terminal electrode electrically connected to the light-emitting element on a peripheral end portion. The terminal electrode provided on the housing so as to be exposed to the outside is in contact with a terminal electrode for the external power supply, so that the external power supply and the light-emitting element are electrically connected to each other and power can be supplied to the lighting device.

Abstract: The present disclosure provides an image sensor semiconductor device. The semiconductor device includes a semiconductor substrate; a first epitaxy semiconductor layer disposed on the semiconductor substrate and having a first type of dopant and a first doping concentration; a second epitaxy semiconductor layer disposed over the first epitaxy semiconductor layer and having the first type of dopant and a second doping concentration less than the first doping concentration; and an image sensor on the second epitaxy semiconductor layer.

Abstract: An optical sensor includes a substrate having an upper surface, a plurality of protrusions on the substrate, wherein each of the plurality of protrusions is defined by a base at the upper surface of the substrate and by one or more sloped surfaces oriented at oblique angles relative to the upper surface, and two or more structural layers in the sloped surfaces. The surfaces of the two or more structural layers can adsorb molecules of a chemical or biological substance.

Abstract: Disclosed is a substrate for display panel that includes, in a pixel, a PIN diode 21 that conducts currents of different values based on the amount of light received, a first inorganic insulating film 11 formed over the PIN diode 21, metal electrodes 12c and 12d that are formed over the first inorganic insulating film 11 and that are connected to the PIN diode 21, an organic insulating film 14 formed over the metal electrodes 12c and 12d, a transparent pixel electrode 15 formed on the organic insulating film 14, and a conductive film 13 that is interposed between the organic insulating film 14 and the first inorganic insulating film 11 and that is patterned so as to partially overlap and partially form an opening with respect to an I-layer 8d of the PIN diode 21.

Abstract: A photodetector is provided that includes a FET structure with a channel structure having one or more nanowire structures. Noble metal nanoparticles are positioned on the channel structure so as to produce a functionalized channel structure. The functionalized channel structure exhibits pronounced surface plasmon resonance (SPR) absorption near the SPR frequency of the noble metal nanoparticles.

Abstract: A mesoporous silica having adjustable pores is obtained to form a template and thus a three-terminal metal-oxide-semiconductor field-effect transistor (MOSFET) photodetector is obtained. A gate dielectric of a nano-structural silicon-base membrane is used as infrared light absorber in it. Thus, a semiconductor photodetector made of pure silicon having a quantum-dot structure is obtained with excellent near-infrared optoelectronic response.

Abstract: An infrared data communication module (A1) includes a substrate (1) consisting of a first layer (1A) and a second layer (1B), where the first layer is formed with a recess (11) open at its obverse surface, and includes the opening of the recess (11) and the second layer is fixed to the first layer (1A) on the side opposite from the opening. The module also includes a bonding conductor layer (6A) covering at least the bottom surface of the recess (11), a light emitting element (2) mounted on the bonding conductor layer (6A), and a heat dissipating conductor layer (6C) sandwiched between the first layer (1A) and the second layer (1B) and connected to the bonding conductor layer (6A).

Abstract: The disclosed subject matter is directed to a reliable surface mount device using a ceramic package, and includes LED devices that are simply composed and incorporate the use of the surface mount device. The surface mount device can include a ceramic package, a semiconductor optical chip mounted in the package, two soldering pads electrically connected to the chip electrodes and at least one dummy soldering pad located on either side of the soldering pads. Thermal fatigue located at or in the soldering connections connecting the chip electrodes to a mounting board can be reduced because the distance between the soldering pads can be reduced. The dummy soldering pad that is electrically insulated can allow the device to maintain a desirable location with poise during the reflow soldering process that occurs during manufacture, and can also reduce shear stress present at the soldering connections.

Abstract: An image sensor includes a trench formed in a semiconductor substrate, a first reflection part formed in the trench and having an inclined, curved surface, a second reflection part formed on the first reflection part such that a remaining space of the trench is filled with the second reflection part, and a vertical type photodiode formed on a region of the substrate between trenches. A method for forming the image sensor includes forming a trench in a semiconductor substrate, forming a first reflection part having an inclined, curved surface in the trench, forming a second reflection part on the first reflection part such that a remaining space of the trench is filled with the second reflection part, and forming a vertical type photodiode on a region of the substrate between trenches.

Abstract: A sensing module comprises a carrier, a sensor, a substrate, and a plurality of chips. The carrier has a carrying surface and a back surface opposite to the carrying surface. The sensor and the substrate are disposed on the carrying surface and are electrically connected to the carrier respectively. The chips are disposed on the substrate and are electrically connected to the substrate respectively. The production cost of the sensing module is low.

Abstract: Photodiode devices with GeSn active layers can be integrated directly on p+ Si platforms under CMOS-compatible conditions. It has been found that even minor amounts of Sn incorporation (2%) dramatically expand the range of IR detection up to at least 1750 nm and substantially increases the absorption. The corresponding photoresponse can cover of all telecommunication bands using entirely group IV materials.

Abstract: A single optical receiver having a photo-detector with a wide optical bandwidth and high efficiency within the wide optical bandwidth, the photo-detector comprising: a first diode region of first doping type for receiving light; a second diode region of second doping type and of second thickness; an active region for converting the received light to an electronic signal, the active region having a third thickness and configured to reside between the first diode region and the second diode region; and a reflector coupled to the second diode region and having a silicon layer with a fourth thickness, the silicon layer residing between silicon oxide layers of fifth thicknesses, wherein the active region is configured to absorb the light of wavelengths of less than 900 nm, and wherein the reflector is configured to reflect the light of wavelengths from a range of 1260 nm to 1380 nm.

Abstract: Method and apparatus are provided for a silicon substrate optical system for use in an interferometric fiber optic gyroscope (IFOG). A silicon substrate of the silicon substrate optical system is etched to receive optical components, including an input optical fiber, a pump source, a wavelength division multiplier, an isolator, a polarizing isolator, a beam splitting device, a PM tap coupler, a relative intensity noise (RIN) photodiode, a system photodiode, and an output optical fiber. The optical components are mounted on a silicon substrate to reduce the size and cost of the IFOG and increase reliability.

Abstract: A photodetector 1 according to an embodiment of the present invention includes: an n-type InAs substrate 12; an n-type InAs buffer layer 14 formed on the n-type InAs substrate 12; an n-type InAs light absorbing layer 16 formed on the n-type InAs buffer layer 14; an InAsXPYSb1-X-Y cap layer 18 (X?0, Y>0) formed on the n-type InAs light absorbing layer 16; a first inorganic insulating film 20 formed on the cap layer 18, and having an opening portion 20h in a deposition direction; a p-type impurity semiconductor region 24 formed by diffusing a p-type impurity from the opening portion 20h of the first inorganic insulating film 20, and reaching from the cap layer 18 to an upper layer of the n-type InAs light absorbing layer 16; and a second inorganic insulating film 22 formed on the first inorganic insulating film 20 and on the p-type impurity semiconductor region 24.

Abstract: Disclosed are various embodiments of a single track reflective optical encoder featuring current amplifiers disposed in the signal generating circuit thereof. Voltage amplifiers and their associated feedback resistors are eliminated in the various embodiments disclosed herein, resulting in decreased die size and improved encoder signal accuracy and performance, especially at high speeds The single track optical encoder configurations disclosed herein permit very high resolution reflective optical encoders in small packages to be provided. Methods of making and using such optical encoders are also disclosed.

Abstract: A photodiode is provided by the invention, including an n-type active region and a p-type active region. A first one of the n-type and p-type active regions is disposed in a semiconductor substrate at a first substrate surface. A second one of the n-type and p-type active regions includes a high-field zone disposed beneath the first one of the active regions at a first depth in the substrate, a mid-field zone disposed laterally outward of the first active region at a second depth in the substrate greater than the first depth, and a step zone connecting the high-field zone and the mid-field zone in the substrate.

Abstract: There is provided an LED package having high heat dissipation efficiency. An LED package according to an aspect of the invention may include: a package body including a first groove portion being recessed into the package body and provided as a mounting area on the top of the package body; first and second lead frames arranged on a lower surface of the first groove portion while parts of the first and second lead frames are exposed; an LED chip mounted onto the lower surface of the first groove portion and electrically connected to the first and second lead frames; and a plurality of heat dissipation patterns provided on the bottom of the package body and formed of carbon nanotubes.

Abstract: According to the present invention, a protective seal S1 for protecting a transparent member 11 is composed of an organic base 16, adhesive layers 17, and a second adhesive layer 18 having low adhesion. The adhesive layers 17 are provided only on edges corresponding, on the organic base 16, to sides 11b of the transparent member and the second adhesive layer 18 is provided on a portion corresponding, on the organic base 16, to a surface 11a of the transparent member. The organic base 16 is fixed to the sides 11b and the surface 11a of the transparent member 11 with the adhesive layers 17 and 18.

Abstract: In an embodiment, the invention provides a proximity sensor including a transmitter die, a receiver die, an ASIC die, a lead frame, wire bonds, a first transparent encapsulant, a second transparent encapsulant, and an opaque encapsulant. The transmitter die, the receiver die and the ASIC die are attached to portions of the lead frame. Wire bonds electrically connect the transmitter die, the receiver die, the ASIC die, and the lead frame. The first transparent encapsulant covers the receiver die, the ASIC die, the wire bonds, and a portion of the lead frame. The second transparent encapsulant covers the transmitter die, the wire bonds, and a portion of the lead frame. The opaque encapsulant covers portions of the first and second encapsulants and a portion of the lead frame.

Abstract: An integrated photonic device includes a number of LEDs and a feedback mechanism that measures individual LED light outputs using a photo sensor via a light transmitter disposed in the vicinity of individual LEDs. A controller or driver adjusts a current driven to each LED using the detected values according to various logic based on the device application.

Abstract: A light emitting device includes: a light emitting element; a first lead including a recess in one end portion, the recess including a first bottom surface with the light emitting element bonded thereto, at least one of a through hole and a notch, and a light shielding portion capable of suppressing leakage of emitted light from the light emitting element from the one of the through hole and the notch; a second lead opposed to the first lead; and a molded body filling the one of the through hole and the notch, covering the light emitting element, embedding at least part of the first lead and at least part of the second lead, and made of a translucent resin.

Abstract: An embedded photodetector apparatus for a three-dimensional complementary metal oxide semiconductor (CMOS) stacked chip assembly having a CMOS chip and one or more thinned CMOS layers is provided. At least one of the one or more thinned CMOS layers includes an active photodiode area defined within the one or more thinned CMOS layers, the active photodiode area being receptive of an optical signal incident thereon, and the active photodiode area comprising a bulk substrate portion of the thinned CMOS layer. The bulk substrate portion has a diode photodetector formed therein.

Abstract: An image sensor having an imaging area that includes a substrate layer and a plurality of pixels formed therein. Multiple pixels each include a photodetector formed in the substrate layer. Isolation layers are formed in the substrate layer by performing a series of implants of one or more dopants of a first conductivity type into the substrate layer. Each isolation layer implant is performed with a different energy than the other isolation layer implants in the series and each implant implants the one or more dopants into the entire imaging area. The photodetectors are formed in the substrate layer by performing a series of implants of one or more dopants of a second conductivity type into each pixel in the substrate layer. Each photodetector implant is performed with a different energy than the other photodetector implants in the series.

Abstract: A sensor includes a substrate provided with a circuit element forming region and a photodiode forming region, the substrate having a silicon substrate, an insulating layer on the silicon substrate, and a silicon layer on the insulating layer; a photodiode in the silicon layer; a circuit element in the silicon layer; a first interlayer insulating film formed over the silicon layer; a first light-shielding film on the first interlayer film and having an opening in the photodiode forming region; and a first inter-region light-shielding plug arranged between the two regions, for connecting the silicon substrate and the first light-shielding film.

Abstract: A reflective touch display panel and a manufacturing method thereof are provided. An incident light enters the display panel through a front substrate thereof. A plurality of pixel structures and a plurality of light sensing devices are disposed on an inner surface of the front substrate. The light sensing device includes a light sensing transistor having a transparent gate electrode. The manufacturing method for the reflective touch display panel includes the following steps. A first patterned transparent conductive layer, including the transparent gate electrode and a capacitance lower electrode, is formed on the front substrate. A first patterned conductive layer, a dielectric layer, a patterned semi-conductive layer, a second patterned conductive layer and a second patterned transparent conductive layer are sequentially formed on the front substrate to respectively form the light sensing device and the pixel structure. A reflective material layer and a back substrate are.

Abstract: A semiconductor photo detector is provided that includes a layer structure deposited over a semiconductor substrate, and having a second mesa formed on the semiconductor substrate and a first mesa formed on the second mesa, wherein an outer periphery of the second mesa is located outside of the outer periphery of the first mesa in two-dimensional view, and wherein surfaces of the first mesa and the second mesa are covered by a passivation film.

Abstract: The present invention provides a multichip LED and method of manufacture in which white light is produced. Specifically, a plurality of electrically interconnected LED chips (e.g., interconnected via red metal wire) is selected for conversion of light to white light. In a typical embodiment, the LED chips comprise: a blue LED chip, a red LED chip, a green LED chip, and a target LED chip whose light output is converted to white light. A wavelength of a light output by one or more of the plurality of chips will be measured. Based on the wavelength measurement, a conformal coating is applied to the one or more of the LED chips. The conformal coating has a phosphor ratio that is based on the wavelength. Moreover, the phosphor ratio is comprised of at least one of the following colors: yellow, green, or red. Using the conformal coating the light output of the target LED is then converted to white light.

Abstract: A system is provided for determining a color using a CMOS image sensor. The system includes an input port for receiving a user command. The system further includes an image sensor, an optical device that forms an image on the image sensor, and a processor. The image sensor includes an n-type substrate and a p-type epitaxy layer overlying the n-type substrate. The image sensor includes a control circuit that applies a first voltage on the n-type substrate to obtain a first output. The control circuit applies a second voltage on the n-type substrate to obtain a second output. The control circuit also applies a third voltage on the n-type substrate to obtain a third output. The p-type epitaxy layer includes a silicon germanium material. The image sensor additionally includes an epitaxy layer interposed between the n-type substrate and the p-type epitaxy layer.

Abstract: A photodiode array includes a p-side electrode provided on each p-type region formed by selective diffusion and an n-side electrode connected to a non-growth part of an InP substrate and extends to the top surface side of an epitaxial multilayer. A wall surface of an edge at the non-growth part side of the epitaxial multilayer is a smooth surface. A lattice defect density in a portion of the edge of the epitaxial multilayer is higher than a lattice defect density in the inside of the epitaxial multilayer. Furthermore, the non-growth part of the InP substrate to which the n-side electrode is connected has a flat surface continuous from the inside of the InP substrate.

Abstract: A radiation detector comprises a voltage applying electrode, a photo-conductor layer, and a charge collecting electrode, which are overlaid one upon another. A selective charge transporting layer is located between the voltage applying electrode and the photo-conductor layer, the selective charge transporting layer having characteristics such that the selective charge transporting layer blocks electric charges having a polarity identical with the polarity of the voltage applying electrode and transports electric charges having a polarity opposite to the polarity of the voltage applying electrode. The selective charge transporting layer takes on the form of a thick film at a position corresponding to an edge region of the voltage applying electrode.

Abstract: There is disclosed a lighting device of which the light sources and/or optical elements are hidden in a first cover state associated with a first light state. This enables an unobtrusive lighting system in the first cover state. In a second cover state associated with a second light state, optical elements, e.g. shutters or beam shaping elements, are switched, induced by the heat or the light flux generated by the light sources, such that the lighting system can function properly.

Abstract: The purpose is manufacturing a photoelectric conversion device with excellent photoelectric conversion characteristics typified by a solar cell with effective use of a silicon material. A single crystal silicon layer is irradiated with a laser beam through an optical modulator to form an uneven structure on a surface thereof. The single crystal silicon layer is obtained in the following manner; an embrittlement layer is formed in a single crystal silicon substrate; one surface of a supporting substrate and one surface of an insulating layer formed over the single crystal silicon substrate are disposed to be in contact and bonded; heat treatment is performed; and the single crystal silicon layer is formed over the supporting substrate by separating part of the single crystal silicon substrate fixed to the supporting substrate along the embrittlement layer or a periphery of the embrittlement layer.

Abstract: A display includes: a substrate having a pixel region and a sensor region in which photo-sensor parts are formed; an illuminating section operative to illuminate the substrate from one surface side of the substrate; a thin film photodiode disposed in the sensor region, having at least a P-type semiconductor region and an N-type semiconductor region, and operative to receive light incident from the other surface side of the substrate; and a metallic film formed on the one surface side of the substrate so as to face the thin film photodiode through an insulator film, operative to restrain light generated from the illuminating section from being directly incident on the thin film photodiode from the one surface side, and fixed to a predetermined potential, wherein in the thin film photodiode, the width of the P-type semiconductor region and the width of the N-type semiconductor region are different from each other.

Abstract: A light emitting apparatus includes a light emitting element formed on a surface of a substrate and a light receiving element formed on an area other than an area overlapping the light emitting element on the surface of the substrate, the light receiving element detecting light emitted from the light emitting element.

Abstract: A method for manufacturing an organic light emitting device including a photo diode and a transistor includes forming a first semiconductor layer and a second semiconductor layer on separate portions of a buffer layer formed on the substrate; forming a gate metal layer on the first semiconductor layer, the gate metal layer covering a central region of the first semiconductor layer; forming a high-concentration P doping region and a high-concentration N doping region in the first semiconductor layer by injecting impurities into regions of the first semiconductor layer not covered by the gate metal layer to form the photodiode; forming a source and drain region and a channel region in the second semiconductor layer; and removing the gate metal layer from the central region of the first semiconductor layer by etching and simultaneously forming a gate electrode by etching, the gate electrode being insulated from the channel region of the second semiconductor layer, to form the transistor.