Abstract: An array of vertical light-emitting diodes includes a flexible substrate-free array of vertical light-emitting diodes having a flexible polymer film forming an insulating organic layer, and a plurality of nanowires embedded in the flexible polymer film. Each of the nanowires is formed by a first and second inorganic semiconductor material or by a first organic and the first inorganic semiconductor material disposed in a respective channel in the flexible polymer film so as to form a pn-hetero-junction.

Abstract: An organic light-emitting display device includes a substrate, a plurality of thin-film transistors on the substrate, each thin-film transistor including an active layer, a planarization layer on the thin-film transistors, a first electrode on the planarization layer and electrically connected to a thin-film transistor, and an ion blocking layer on the planarization layer, the ion blocking layer overlapping the active layer.

Abstract: A method for manufacturing an oxide thin film transistor includes the steps of forming an oxide semiconductor active layer by a deposition process. In the deposition process, a total flow rate of a gas is more than 100 standard cubic centimeters per minute and an electric power is in a range from 1.5 kilowatts to 10 kilowatts. The oxide thin film transistor manufactured by the above methods has advantages of low leakage currents, high electron mobility, and excellent temperature stability. The present invention also provides a method for manufacturing a display device. The display quality of the display device can be improved.

Abstract: Disclosed is a semiconductor light-emitting device wherein a pn junction is formed by forming, as a p-type layer (11), a semiconductor thin film which is composed of a ZnO compound doped with nitrogen on an n-type ZnO bulk single crystal substrate (10) whose resistance is lowered by being doped with donor impurities. It is preferable to form the p-type layer (11) on a zinc atom containing surface of the n-type ZnO bulk single crystal substrate (10).

Abstract: It is an object of the present invention to provide a light-emitting device in which, even when a material with high reflectivity such as aluminum is used for an electrode, a layer containing oxygen can be formed over the electrode without increasing contact resistance and a manufacturing method thereof. According to the present invention, a feature thereof is a light-emitting element having an electrode composed of a stacked structure where a conductive film having high reflectivity such as aluminum, silver, and an alloy containing aluminum or an alloy containing silver, and a conductive film composed of a refractory metal material is provided over the conductive film, or a light-emitting device having the light-emitting element.

Abstract: A technique is disclosed to stabilize the threshold voltage of a transistor having an active layer formed of a metal oxide. The transistor includes a first metal oxide layer, a second metal oxide layer that is greater in sheet resistance than the first metal oxide layer, a pair of an input electrode and an output electrode that are electrically connected to the first metal oxide layer, and a control electrode that controls an impedance between the input electrode and the output electrode. The control electrode, the first metal oxide layer, and the second metal oxide layer are arranged in the stated order.

Abstract: An organic light emitting display device and a method for manufacturing the same. The organic light emitting display device includes: an insulating layer formed on a substrate; a resistance layer of oxide semiconductor formed on the insulating layer; a wiring layer connected to both side portions of the resistance layer; an organic layer formed on the upper portion including the resistance layer and the wiring layer; and a capping layer formed on the organic layer to be overlapped with the resistance layer.

Abstract: Provided are a transistor, a method of manufacturing the transistor, and an electronic device including the transistor. The transistor may include a passivation layer on a channel layer, a source, a drain, and a gate, wherein the component of the passivation layer is varied in a height direction. The passivation layer may have a multi-layer structure including a silicon oxide layer, a silicon oxynitride layer, and a silicon nitride layer sequentially stacked. The channel layer may include an oxide semiconductor.

Abstract: A field effect transistor includes a gate electrode to which a gate voltage is applied; a source electrode and a drain electrode for obtaining a current in response to the gate voltage; an active layer provided adjacent to the source electrode and the drain electrode and formed of an oxide semiconductor including magnesium and indium as major components; and a gate insulating layer provided between the gate electrode and the active layer.

Abstract: Disclosed are a liquid crystal display device employing an amorphous zinc oxide-based semiconductor as an active layer, and a method for fabricating the same, whereby device stability can be secured by employing an etch stopper structure and device characteristics can be enhanced by minimizing exposure and deterioration of the active layer excluding content regions by virtue of the design of the etching stopper in a shape like “H”. Also, the liquid crystal display device and the fabrication method thereof can further form a semiconductor pattern and an insulating layer pattern on the intersection between the gate line and the data line, so as to compensate a stepped portion, thereby preventing an occurrence of short-circuit.

Abstract: A method is provided for anisotropically etching semiconductor materials such as II-VI and III-V semiconductors. The method involves repeated cycles of plasma sputter etching of semiconductor material with a non-reactive gas through an etch mask, followed by passivation of the side walls by plasma polymerization using a polymer former. Using this procedure small pixels in down-converted light-emitting diode devices can be fabricated.

Abstract: Provided is a light emitting device, which includes a first conductive type semiconductor layer, an active layer, a roughness pattern, and a second conductive type semiconductor layer. The active layer is disposed on the first conductive type semiconductor layer. The roughness pattern is disposed on the active layer. The second conductive type semiconductor layer is disposed on the roughness pattern and the active layer, and includes a metal oxide.

Abstract: There is provided a thin film transistor capable of suppressing generation of a leak current in an oxide semiconductor film. A thin film transistor 1 includes a gate electrode 12 on a substrate 11, and includes a gate insulating film 13 so as to cover the gate electrode 12 and the substrate 11. An oxide semiconductor film 14 is formed in a region corresponding to the gate electrode 12 on the gate insulating film 13, and a source electrode 15A and a drain electrode 15B are provided with a predetermined interval in between on the oxide semiconductor film 14. A protective film 16 is formed over a whole surface of the substrate 11 so as to cover a channel region 14A of the oxide semiconductor film 14, the source electrode 15A, and the drain electrode 15B. The protective film 16 is composed of an aluminum oxide film, and this aluminum oxide film is formed by an atomic layer deposition method. An entry of hydrogen into the oxide semiconductor film 14 is suppressed by the protective film 16.

Abstract: Optoelectronic devices, junctions and methods of fabricating a device or junction where the emitter layer is of an indirect-band-gap material and the base layer is of a direct-band-gap material. The device or junction may have, among other structures and layers, a base layer of a first semiconductor material having a first conductivity type and further having a direct band gap and an emitter layer forming a junction with the base layer. In this embodiment, the emitter layer may be of a second semiconductor material having a second conductivity type and further having an indirect band gap. The optoelectronic device may have the semiconductor material of the emitter layer substantially lattice mismatched with the semiconductor material of the base layer in bulk form. Alternatively, the emitter layer may be substantially lattice matched with the base layer.

Abstract: Disclosed is a semiconductor device which consumes low power and has high reliability and tolerance for electrostatic discharge. The semiconductor device includes, over a first substrate, a pixel portion and a driver circuit portion both of which have a thin film transistor having an oxide semiconductor layer. The semiconductor device further possesses a second substrate to which a first counter electrode layer and a second counter electrode layer are provided, and a liquid crystal layer is interposed between the first and second substrates. The first and second counter electrode layers are provided over the pixel portion and the driver circuit portion, respectively, and the second counter electrode layer has the same potential as the first counter electrode layer.

Abstract: An object is to provide an active matrix liquid crystal display device in which plural kinds of circuits are formed over one substrate and plural kinds of thin film transistors are provided corresponding to characteristics of the plural kinds of circuits. An inverted-coplanar thin film transistor including an oxide semiconductor layer which is over and overlaps with a source electrode layer and a drain electrode layer is used for a pixel thin film transistor. A channel-protective thin film transistor is used for a driver-circuit thin film transistor is used. In addition, main parts of the pixel thin film transistor are formed using a light-transmitting material, so that the aperture ratio is increased.

Abstract: A method is provided for growing a stable p-type ZnO thin film with low resistivity and high mobility. The method includes providing an n-type Li—Ni co-doped ZnO target in a chamber, providing a substrate in the chamber, and ablating the target to form the thin film on the substrate.

Abstract: An object is to provide a display device with excellent display characteristics, where a pixel circuit and a driver circuit provided over one substrate are formed using transistors which have different structures corresponding to characteristics of the respective circuits. The driver circuit portion includes a driver circuit transistor in which a gate electrode layer, a source electrode layer, and a drain electrode layer are formed using a metal film, and a channel layer is formed using an oxide semiconductor. The pixel portion includes a pixel transistor in which a gate electrode layer, a source electrode layer, and a drain electrode layer are formed using an oxide conductor, and a semiconductor layer is formed using an oxide semiconductor. The pixel transistor is formed using a light-transmitting material, and thus, a display device with higher aperture ratio can be manufactured.

Abstract: Crystalline inorganic-organic hybrid structures having a plurality of layers of a repeating unit characterized by a first organic ligand layer, a second organic ligand layer, and a two-dimensional semiconducting inorganic double layer having two opposing surfaces therebetween, wherein the two-dimentional semiconducting inorganic double layer is characterized by two single atom thick layers of a II-chalcogenide compound; and the first organic ligand layer and the second organic ligand layer are attached to the two opposing surfaces of the two-dimensional semiconducting inorganic double layer through a covalent bond or a coordinate covalent bond between the compounds of the organic ligand layers and the metal cation species of the II-VI chalcogenide compounds, so that the semiconducting inorganic double layer is directed by the compounds of the two opposing organic layers to form ordered crystal lattices. Methods for the preparation of the hybrid structures are also disclosed.

Abstract: An organic light emitting display device including a plurality of scan lines arranged in a first direction, a plurality of data lines arranged in a second direction, the plurality of data lines intersecting with the plurality of scan lines, and pixels respectively disposed at intersection portions of the scan and data lines, each pixel including at least one thin film transistor (TFT) and an organic light emitting diode, wherein the TFT is an oxide TFT, the oxide TFT including a first oxide semiconductor layer as an active layer, and a second oxide semiconductor layer is disposed between intersecting scan and data lines.

Abstract: A nanodevice, a transistor including the nanodevice, a method of manufacturing the nanodevice, and a method of manufacturing the transistor including the nanodevice are provided. The nanodevice includes a substrate, a mask layer located on the substrate and having at least one opening, and a nanotube formed on the substrate through the opening along an edge of the opening. The nanotube extends through the opening in a direction substantially perpendicular to a surface of the substrate.

Abstract: An organic light emitting display includes data lines and scan lines intersecting each other, a scan driving unit for supplying a scan signal to the scan lines, a data driving unit for supplying a data signal to the data lines, and pixels defined at intersection points of the data and scan lines, each pixel having an organic light emitting diode, a first TFT with an inverted staggered top gate structure and connected to the organic light emitting diode, the first TFT including an oxide semiconductor as an active layer, and a second TFT with an inverted staggered bottom gate structure and configured to receive the scan signal from the scan lines, the second TFT including an oxide semiconductor as an active layer.

Abstract: Provided is a thin-film transistor (TFT) display panel having improved electrical and reliability properties and a method of fabricating the TFT display panel. The TFT display panel includes gate wiring formed on a substrate; an oxide active layer pattern formed on the gate wiring; data wiring formed on the oxide active layer pattern to cross the gate wiring; a passivation layer formed on the oxide active layer pattern and the data wiring and made of nitrogen oxide; and a pixel electrode disposed on the passivation layer.

Abstract: Semiconductor emitting devices that offset stresses applied to a quantum well region and reduce internal fields due to spontaneous and piezoelectric polarizations are disclosed. In one embodiment, a semiconductor emitting device includes a quantum well region comprising an active layer that emits light and at least one barrier layer disposed adjacent the active layer, a means for impressing an electric field across the quantum well region to inject carriers into the quantum well region, and a means for impressing an offset electric field across the quantum well region to offset the polarization field formed in the quantum well region.

Abstract: An array substrate including a substrate having a pixel region, a gate line and a gate electrode on the substrate, the gate electrode being connected to the gate line, a gate insulating layer on the gate line and the gate electrode, an oxide semiconductor layer on the gate insulating layer, an auxiliary pattern on the oxide semiconductor layer, and source and drain electrodes on the auxiliary pattern, the source and drain electrodes being disposed over the auxiliary pattern and spaced apart from each other to expose a portion of the auxiliary pattern. Further, the exposed portion of the auxiliary pattern exposes a channel region and including a metal oxide over the channel region.

Abstract: A method for fabricating a liquid crystal display (LCD) device include: forming a gate electrode on a substrate; forming a gate insulating layer on the substrate; forming a primary active layer having a tapered portion to a side of a channel region of the primary active layer on the gate insulating layer, and forming source and drain electrodes on the primary active layer; and forming a secondary active layer made of amorphous zinc oxide-based semiconductor on the source and drain electrodes and being in contact with the tapered portion of the primary active layer, wherein the primary active layer is etched at a low selectivity during a wet etching of the source and drain electrodes, to have the tapered portion.

Abstract: A display device including an oxide thin film transistor (TFT) is disclosed. A nitride-based gate insulating layer of a gate pad area is etched when an oxide semiconductor layer of a pixel area is etched by using a half-tone mask, a metal layer is formed at a contact hole of the etched gate insulting layer, and then a passivation layer formed thereon is etched. Thus, an overhang of the passivation layer can be prevented from being generated when the gate insulating layer is etched, and accordingly, the fabrication process can be simplified.

Abstract: As a display device has higher definition, the number of pixels is increased and thus, the number of gate lines and signal lines is increased. When the number of gate lines and signal lines is increased, it is difficult to mount IC chips including driver circuits for driving the gate lines and the signal lines by bonding or the like, whereby manufacturing cost is increased. A pixel portion and a driver circuit for driving the pixel portion are provided on the same substrate, and at least part of the driver circuit comprises a thin film transistor including an oxide semiconductor sandwiched between gate electrodes. A channel protective layer is provided between the oxide semiconductor and a gate electrode provided over the oxide semiconductor. The pixel portion and the driver circuit are provided on the same substrate, which leads to reduction of manufacturing cost.

Abstract: A method for manufacturing a light-emitting diode includes the steps of: growing a light-emitting diode structure-forming semiconductor layer of a compound semiconductor having a zincblende crystal structure on a first substrate formed of a compound semiconductor having a zincblende crystal structure and that has a principal surface tilted in a [110] direction with respect to a (001) plane; bonding the first substrate to a second substrate on the side of the semiconductor layer; removing the first substrate so as to expose the semiconductor layer; forming an etching mask on the exposed surface of the semiconductor layer in a rectangular planar shape so that a longer side extends in a [110] or [?1-10] direction, and that a shorter side extends in a [?110] or [1-10] direction; and patterning the semiconductor layer by wet etching using the etching mask.

Abstract: An active matrix display comprising a light control device and a field effect transistor for driving the light control device. The active layer of the field effect transistor comprises an amorphous.

Abstract: A method which has a low-temperature growth step of growing a buffer layer of a ZnO-based single crystal on the substrate at a growth temperature in the range of 250° C. to 450° C. using a polar oxygen material and a metalorganic compound containing no oxygen; performing a heat treatment of the buffer layer to effect a transition of the buffer layer to a thermostable-state single crystal layer; and a high-temperature growth step of growing the ZnO-based single crystal layer on the thermostable-state single crystal layer at a growth temperature in the range of 600° C. to 900° C. using a polar oxygen material and a metalorganic compound containing no oxygen.

Abstract: A heterostructure semiconductor device capable of emitting electromagnetic radiation and having a junction with opposite conductivity type materials on either side thereof supported on a substrate with an active layer therebetween comprising zinc oxide and having a band gap energy that is less than that of either of the opposite conductivity type materials.

Abstract: There is provided a ZnO based compound semiconductor light emitting device which can emit light with high efficiency and from an entire surface while using ZnO based compound semiconductor which can be expected with higher light emitting efficiency than that of a GaN based compound. On an insulating substrate (1), an n-type layer (2), an active layer (3), and a p-type layer (4), made of ZnO based compound semiconductor materials, are laminated, wherein a specific resistance of the n-type layer is 0.001 ?·cm or more and 1 ?·cm or less, and a film thickness (?m) of the n-type layer is set in a value or more calculated by a formula (specific resistance (?·cm))×300, and an n-side electrode (5) is formed on an exposed portion of a surface of the n-type layer opposite to a surface being in contact with the substrate and a p-side electrode (6) is formed on the p-type layer.

Abstract: Disclosed is a method of manufacturing a ZnO-based semiconductor device having at least p-type ZnO-based semiconductor layer, which includes a step of forming a contact metal layer on the p-type ZnO-based semiconductor layer wherein the contact metal layer contains at least one of Ni and Cu; and a step of performing heat treatment of the contact metal layer and the p-type ZnO-based semiconductor layer under an oxygen-free atmosphere to form a mixture layer including elements of the p-type ZnO-based semiconductor layer and the contact metal layer at a boundary region therebetween while maintaining a metal phase layer on a surface of the contact metal layer.

Abstract: An organic electroluminescent device is provided, including at least one light emitting layer 5 composed of an organic material between a transparent electrode and a counter electrode, wherein the organic electroluminescent device includes an electron injection layer 6 previously provided on the organic layer side of the counter electrode which is contact disposed in a solid plate form on the organic layer and heat and pressure formed, and the electron injection layer 6 is constituted of a metal oxide. According to this configuration, it is possible to heat soften the counter electrode in a fixed plate form and join it, and it is possible to inexpensively manufacture the organic electroluminescent device 1 with ease.

Abstract: An object is to provide a semiconductor device provided with a thin film transistor having excellent electric characteristics using an oxide semiconductor layer. An In—Sn—O-based oxide semiconductor layer including SiOX is used for a channel formation region. In order to reduce contact resistance between the In—Sn—O-based oxide semiconductor layer including SiOX and a wiring layer formed from a metal material having low electric resistance, a source region or drain region is formed between a source electrode layer or drain electrode layer and the In—Sn—O-based oxide semiconductor layer including SiOX. The source region or drain region and a pixel region are formed using an In—Sn—O-based oxide semiconductor layer which does not include SiOX.

Abstract: A thin-film transistor includes: a gate electrode formed on a substrate; an oxide semiconductor layer forming a channel region corresponding to the gate electrode; a first gate insulating film formed on the substrate and the gate electrode, and including a silicon nitride film; a second gate insulating film selectively formed to contact with the oxide semiconductor layer in a region, on the first gate insulating film, corresponding to the oxide semiconductor layer, and including one of a silicon oxide film and a silicon oxynitride film; a source/drain electrode; and a protecting film. An upper surface and a side surface of the oxide semiconductor layer and a side surface of the second gate insulating film are covered, on the first gate insulating film, by the source/drain electrode and the protecting film.

Abstract: An oxide semiconductor thin film transistor and a flat panel display device incorporating the same oxide semiconductor thin film transistor. The thin film transistor includes a gate electrode formed on the substrate, a gate insulating layer formed on the substrate and covering the gate electrode, an oxide semiconductor layer formed on the gate insulating layer and covering the gate electrode, a titanium layer formed in a source region and a drain region of the oxide semiconductor layer, and source and drain electrodes respectively coupled to the source region and the drain region through the titanium layer and made of copper. The titanium layer reduces the contact resistance between the source and drain electrodes made of copper and the oxide semiconductor layer, forms a stable interface junction therebetween, and blocks a diffusion of copper.

Abstract: Provided is a zinc oxide light emitting diode having improved optical characteristics. The zinc oxide light emitting diode includes an n-type semiconductor layer, a zinc oxide active layer formed on the n-type semiconductor layer, a p-type semiconductor layer formed on the active layer, an anode in electrical contact with the p-type semiconductor layer, a cathode in electrical contact with the n-type semiconductor layer, and a surface plasmon layer disposed between the n-type semiconductor layer and the active layer or between the active layer and the p-type semiconductor layer. Since the surface plasmon layer is formed between the n-type semiconductor layer and the active layer or between the active layer and the p-type semiconductor layer, the light emitting diode is not affected by an increase in resistance due to reduction of the thickness of the p-type semiconductor layer, and has improved optical characteristics due to a resonance phenomenon between the surface plasmon layer and the active layer.

Abstract: A thin film field effect transistor includes at least: a substrate; and a gate electrode, a gate insulating layer, an active layer, a source electrode and a drain electrode, and a protective layer provided on the substrate in this order from the substrate side. The active layer is a layer containing an amorphous oxide containing at least one metal selected from the group consisting of In, Sn, Zn and Cd. The thin film field effect transistor further includes, between the active layer and at least one of the source electrode or the drain electrode, an electric resistance layer containing an oxide or nitride containing at least one metal selected from the group consisting of Ga, Al, Mg, Ca and Si.

Abstract: A display device includes a first wiring functioning as a gate electrode formed over a substrate, a gate insulating film formed over the first wiring, a second wiring and an electrode layer provided over the gate insulating film, and a high-resistance oxide semiconductor layer formed between the second wiring and the electrode layer are included. In the structure, the second wiring is formed using a stack of a low-resistance oxide semiconductor layer and a conductive layer over the low-resistance oxide semiconductor layer, and the electrode layer is formed using a stack of the low-resistance oxide semiconductor layer and the conductive layer which is stacked so that a region functioning as a pixel electrode of the low-resistance oxide semiconductor layer is exposed.

Abstract: A manufacture method for a ZnO based semiconductor device includes the steps of: (a) preparing a ZnO based semiconductor wafer including a ZnO based semiconductor substrate having a wurzeit structure with a +C plane on one surface and a ?C plane on an opposite surface, a first ZnO based semiconductor layer having a first conductivity type epitaxially grown above the +C plane of the ZnO based semiconductor substrate, and a second ZnO based semiconductor layer having a second conductivity type opposite to the first conductivity type epitaxially grown above the first semiconductor layer; and (b) wet-etching the ZnO based semiconductor wafer with acid etching liquid to etch the ?C plane of the ZnO based semiconductor substrate

Abstract: An object of the invention is to provide a TFT substrate and a method for producing a TFT substrate which is capable of drastically reducing the production cost by decreasing the number of steps in the production process and improving production yield. A TFT substrate includes: a substrate; a gate electrode and a gate wire formed above the substrate; a gate insulating film formed above the gate electrode and the gate wire; a first oxide layer formed above the gate insulating film which is formed at least above the gate electrode; and a second oxide layer formed above the first oxide layer; wherein at least a pixel electrode is formed from the second oxide layer.

Abstract: Mg is doped in a ZnO-containing semiconductor layer in a concentration range from 1×1017 cm?3 to 2×1020 cm?3.

Abstract: To provide a light emitting apparatus in which high definition can be realized and the connection reliability of a wiring portion is excellent, the light emitting apparatus includes: a substrate; a light emitting element which includes a first electrode, an emission layer, and a second electrode which are stacked on the substrate in the stated order; and a thin film transistor which is of an n-type and includes a channel layer and a drain electrode, the light emitting element and the thin film transistor are arranged in parallel and in contact with the substrate, the channel layer of the thin film transistor has a field effect mobility equal to or larger than 1 cm2V?1s?1, and the second electrode is connected with the drain electrode of the thin film transistor.

Abstract: A light-emitting device, such as a light-emitting diode (LED), includes a substrate including a ZnO-based material, and a structure disposed on a first side of the substrate. The structure includes a plurality of semiconductor layers and an active layer disposed between the plurality of semiconductor layers. The device further includes at least one textured light emission surface arranged to extract at least some light generated within the device.

Abstract: As a display device has a higher definition, the number of pixels, gate lines, and signal lines are increased. When the number of the gate lines and the signal lines are increased, there occurs a problem that it is difficult to mount an IC chip including a driver circuit for driving the gate and signal lines by bonding or the like, whereby manufacturing cost is increased. A pixel portion and a driver circuit for driving the pixel portion are provided over the same substrate, and at least part of the driver circuit includes a thin film transistor using an oxide semiconductor interposed between gate electrodes provided above and below the oxide semiconductor. The pixel portion and the driver portion are provided over the same substrate, whereby manufacturing cost can be reduced.

Abstract: The protective circuit is formed using a non-linear element which includes a gate insulating film covering a gate electrode; a first wiring layer and a second wiring layer which are over the gate insulating film and whose end portions overlap with the gate electrode; and an oxide semiconductor layer which is over the gate electrode and in contact with the gate insulating film and the end portions of the first wiring layer and the second wiring layer. The gate electrode of the non-linear element and a scan line or a signal line is included in a wiring, the first or second wiring layer of the non-linear element is directly connected to the wiring so as to apply the potential of the gate electrode.

Abstract: A display device including an oxide semiconductor, a protective circuit and the like having appropriate structures and a small occupied area is necessary. The protective circuit is formed using a non-linear element which includes a gate insulating film covering a gate electrode; a first oxide semiconductor layer which is over the gate insulating layer and overlaps with the gate electrode; and a first wiring layer and a second wiring layer each of which is formed by stacking a conductive layer and a second oxide semiconductor layer and whose end portions are over the first oxide semiconductor layer and overlap with the gate electrode. The gate electrode of the non-linear element is connected to a scan line or a signal line, the first wiring layer or the second wiring layer of the non-linear element is directly connected to the gate electrode layer so as to apply potential of the gate electrode.

Abstract: With an increase in the definition of a display device, the number of pixels is increased, and thus the numbers of gate lines and signal lines are increased. Due to the increase in the numbers of gate lines and signal lines, it is difficult to mount an IC chip having a driver circuit for driving the gate and signal lines by bonding or the like, which causes an increase in manufacturing costs. A pixel portion and a driver circuit for driving the pixel portion are formed over one substrate. At least a part of the driver circuit is formed using an inverted staggered thin film transistor in which an oxide semiconductor is used. The driver circuit as well as the pixel portion is provided over the same substrate, whereby manufacturing costs are reduced.