Abstract: Embodiments of the systems, methods, and computer readable medium devices disclosed herein provide a sentiment analysis system that can determine sentiment from an input of a user received from a device. Once the input is received, parsing and analysis can be performed to determine a particular sentiment corresponding to the input. The system can determine an overall sentiment of some or all of the users or viewers watching a particular video stream, such as a live video stream. The determined overall sentiment can represent a metric indicating what users generally feel about a portion of the video stream, and the system can use the determination to cause modification of the video stream or a future video stream to enhance the user experience.

Abstract: A semiconductor device comprising a plurality of regions of semiconductor material forming a junction at an interface there-between, the junction including a depletion region having a width which varies spatially in at least one direction along the depletion region. Without limitation, the spatial variation in depletion region width is provided by ionised dopants having a concentration which varies spatially along said at least one direction. Alternatively, or in addition, the spatial variation in depletion region width is achieved by varying the thickness of the region(s) of semiconductor spatially along said at least one direction, for example by creating a plurality of cells within said region(s) devoid of said semiconductor material. A method of fabricating a semiconductor device comprising the step of varying the width of the depletion region spatially there-within in at least one direction along the depletion region.

Abstract: An improved photocell offering efficient power generation from broadband incident radiation, the photocell includes a first diode formed in single crystal silicon and one or more further diodes each formed in a single crystal Group II-VI semiconductor. In a preferred embodiment, a tandem photocell is provided that incorporates a first diode formed in single crystal silicon, a second diode formed in a Group II-VI semiconductor, an optional buffer layer and a highly doped layer of silicon acting as an optional tunnel junction between the two diodes. The device can additionally include a layer of silicon deposited at the rear of the structure to maximise current collection of longer wavelength light, and top and bottom (front and back) electrical contacts. In use, light impinges on the top (front) surface of the photocell and is absorbed (in turn) by diodes.

Abstract: A photocell which operates at multiple wavelengths for efficient power generation from broadband incident radiation. According to a preferred embodiment, the photocell is a multi-layer device that includes a first outer layer, a middle layer and an inner layer disposed on a substrate. All three layers are formed from II-VI semiconductor layers. The device is arranged such that the outer layer has a high band gap, the middle layer has a band gap which is less than half the band gap of the outer layer and the inner layer has a band gap which is less than half that of the substrate. Thus, there is a step change in band gap between various layers.

Abstract: In a transistor in which the majority carriers are holes, at least one narrow bandgap region or layer is doped p-type or contains an excess of holes and is subject to compressive mechanical strain, whereby hole mobility may be significantly increased. In a p-channel quantum well FET, the quantum well InSb well p-type layer 5 (modulation or directly doped) lies between In1-xAlxSb layers 4, 6 where x is of a value sufficient to induce strain in layer 5 to an extent that light and heavy holes are separated by much more than kT. Transistors falling within the invention, including bipolar pnp devices, may be used with their more conventional electron majority carriers counterparts in complementary logic circuitry.

Abstract: A semiconductor device comprising a plurality of regions of semiconductor material forming a junction at an interface there-between, the junction including a depletion region having a width which varies spatially in at least one direction along the depletion region. Without limitation, the spatial variation in depletion region width is provided by ionised dopants having a concentration which varies spatially along said at least one direction. Alternatively, or in addition, the spatial variation in depletion region width is achieved by varying the thickness of the region(s) of semiconductor spatially along said at least one direction, for example by creating a plurality of cells within said region(s) devoid of said semiconductor material. A method of fabricating a semiconductor device comprising the step of varying the width of the depletion region spatially there-within in at least one direction along the depletion region.

Abstract: A communications system incorporates a transmitter a receiver. The transmitter includes an infrared light emitting diode (LED). The LED output is positive or negative luminescence, i.e. above or below an equilibrium background intensity level respectively, according to the polarity of its bias signal. The receiver contains a lens to focus light from the LED onto a diode detector, from which signals pass to an amplifier, decoder and printer. Output signals from the LED have an average intensity equal to the equilibrium background intensity level and a frequency greater than 100 Hz or byte rate greater than 100 bytes/sec. They are not discernible by conventional thermal infrared imagers with frame rates of 50 Hz or less because integration in such an imager renders them indistinguishable from background.

Abstract: A molecular single electron transistor (MSET) detector device (14) is described that comprises at least one organic molecule (87) connecting a drain electrode (84) and a source electrode (82). In use, said at least one organic molecule (87) provides a quantum confinement region. At least one analyte receptor site (90, 92) is provided in the vicinity of said at least one organic molecule (87) that bind molecules of interest (analytes). A fluid analyser (2) is also described that includes the MSET detector, a pre-concentrator (4) and a fluid gating structure (6). The fluid gating structure (6) is arranged to selectively route fluid from the pre-concentrator (4) to either one of the detector (14) and an exhaust port (12). The pre-concentrator (4), fluid gating structure (6) and detector (14) are each formed as substantially planar layers and arranged in a stack or cube.

Abstract: A molecular single electron transistor (MSET) detector device (14) is described that comprises at least one organic molecule (87) connecting a drain electrode (84) and a source electrode (82). In use, said at least one organic molecule (87) provides a quantum confinement region. At least one analyte receptor site (90, 92) is provided in the vicinity of said at least one organic molecule (87) that bind molecules of interest (analytes). A fluid analyser (2) is also described that includes the MSET detector, a pre-concentrator (4) and a fluid gating structure (6). The fluid gating structure (6) is arranged to selectively route fluid from the pre-concentrator (4) to either one of the detector (14) and an exhaust port (12). The pre-concentrator (4), fluid gating structure (6) and detector (14) are each formed as substantially planar layers and arranged in a stack or cube.

Abstract: In a transistor in which the majority carriers are holes, at least one narrow bandgap region or layer is doped p-type or contains an excess of holes and is subject to compressive mechanical strain, whereby hole mobility may be significantly increased. In a p-channel quantum well FET, the quantum well InSb well p-type layer 5 (modulation or directly doped) lies between In1-xAlxSb layers 4, 6 where x is of a value sufficient to induce strain in layer 5 to an extent that light and heavy holes are separated by much more than kT. Transistors falling within the invention, including bipolar pnp devices, may be used with their more conventional electron majority carriers counterparts in complementary logic circuitry.

Abstract: An infrared light emitting diode arrangement comprising an infrared light emitting diode which emits positive luminescence when forward biased and emits negative luminescence when reverse biased. The diode is driven by an alternating forward and reverse bias input so that the difference in output power between the positive luminescence and the negative luminescence of the light emitting diode is stabilised with respect to temperature. The infrared light emitting diode arrangement has particular application as a source in gas sensors and reduces or eliminates temperature control requirements for infrared light emitting diode sources.

Abstract: The invention provides a Hall effect magnetic field sensor (10, 50) including carrier excluding or extracting means (36, 66) for reducing an intrinsic contribution to carrier concentration in the active region (14e, 53c) to provide for the sensor to be operative in an extrinsic saturated regime. This provides an advantage that magnetic field measurement sensitivity of the sensor (10, 50) can be made substantially insensitive to sensor temperature thereby improving measurement accuracy.

Abstract: A field effect transistor (FET) is of the type which employs base biasing to depress the intrinsic contribution to conduction and reduce leakage current. It incorporates four successive layers (102 to 108): a p+ InSb base layer (102), a p+ InAlSb barrier layer (104), a &pgr; intrinsic layer (106) and an insulating SiO2 layer (108); p+ source and drain regions (110, 112) are implanted in the intrinsic layer (106). The FET is an enhancement mode MISFET (100) in which biasing establishes the FET channel in the intrinsic layer (106). The insulating layer (108) has a substantially flat surface supporting a gate contact (116). This avoids or reduces departures from channel straightness caused by intrusion of a gate groove, and enables a high value of current gain cut-off frequency to be obtained. In FETs with layers that are not flat, departures from channel straightness should not be more than 50 nm in extent, preferably less than 5 nm.

Abstract: The invention provides a Hall effect magnetic field sensor (10, 50) including carrier excluding or extracting means (36, 66) for reducing an intrinsic contribution to carrier concentration in the active region (14e, 53c) to provide for the sensor to be operative in an extrinsic saturated regime. This provides an advantage that magnetic field measurement sensitivity of the sensor (10, 50) can be made substantially insensitive to sensor temperature thereby improving measurement accuracy.

Abstract: A semiconductor device wherein the layer of highly doped p-type material typically found in devices of the prior art is replaced with a layer of doped n-type material, having a doping concentration of between 1×1018 cm−3 and less than 1×1019 cm−3, and a thin layer of doped p type material thus facilitating low resistance contact, transparency to radiation produced by the device and confinement with low loss of radiation produced by laser devices.

Abstract: A field effect transistor (FET) is of the type which employs base biasing to depress the intrinsic contribution to conduction and reduce leakage current. It incorporates four successive layers (102 to 108): a p+ InSb base layer (102), a p+ InAlSb barrier layer (104), a &pgr; intrinsic layer (106) and an insulating SiO2 layer (108); p+ source and drain regions (110, 112) are implanted in the intrinsic layer (106). The FET is an enhancement mode MISFET (100) in which biasing establishes the FET channel in the intrinsic layer (106). The insulating layer (108) has a substantially flat surface supporting a gate contact (116). This avoids or reduces departures from channel straightness caused by intrusion of a gate groove, and enables a high value of current gain cut-off frequency to be obtained. In FETs with layers that are not flat, departures from channel straightness should not be more than 50 nm in extent, preferably less than 5 nm.

Abstract: A thermal imaging system (10) which is accoupled and by scanning recreates a thermal image by superimposing measured variations in infrared emission from a scene (22) onto a reference level supplied by a light emitting diode (28). The diode (28) is both a positive and negative luminescent emitter. Emitted flux is current controlled to be equivalent to black body radiation at a range of temperatures which may be colder or hotter than ambient. A signal generated with the system (10) switches between scene and diode observation is a measure of the difference between the mean scene temperature and the diode effective temperature. In response to this digital, control means adjust the bias current through the diode (28) in order to reduce the temperature difference. The reference temperature converges towards the mean scene temperature as this process is repeated. Absolute temperature is thus restored and some image defects removed.

Abstract: A semiconductor device wherein the layer of highly doped p-type material typically found in devices of the prior art is replaced with a layer of doped n-type material, having a doping concentration of between 1.times.10.sup.18 cm.sup.-3 and less than 1.times.10.sup.19 cm.sup.-3, and a thin layer of doped p type material thus facilitating low resistance contact, transparency to radiation produced by the device and confinement with low loss of radiation produced by laser devices.

Abstract: A thermal sensing system (10) including an array of photon detectors (14) produces a detector-dependent response to irradiation. Variations in individual detector characteristics produce a fixed pattern noise which degrades an image or other response. A switchable mirror (M1) may at one position (P.sub.cal) direct infrared radiation from a light emitting diode (20) onto the detector array (14). The diode (20) is both a negative and positive luminescent emitter, the flux emitted is current controlled to be equivalent to black body radiation at a range of temperatures both colder and hotter than ambient. Calibration relationships comprising transfer functions relating incident intensity to signal response are derived for each detector. Alternatively the mirror (M1) may be at an observation position (P.sub.obs) and infrared radiation from a remote scene reaches the detector array (14).

Abstract: An infrared optical system incorporates a lens for imaging a remote scene onto a detector within a cold shield. Stray radiation incident on the detector is reduced by an optical stop in the form of a light emitting diode producing negative luminescence. The LED emits less radiation than background, and contributes less to the detector photon noise than an optical stop not exhibiting negative luminescence.