Abstract: A photodetector array comprising at least one first sensor and at least one second sensor on the horizontal surface of the array substrate. The at least one first sensor is sensitive to radiation in a first wavelength range which comprises long-wavelength infrared wavelengths, and the at least one second sensor is sensitive to radiation in a second wavelength range which comprises wavelengths shorter than long-wavelength infrared. The array substrate comprises a vertical cavity on its horizontal surface, and the first sensor comprises a layer of pyroelectric material (65) which extends horizontally across the vertical cavity in the first area. A first part of a layer of two-dimensional layered material at least partly covers the layer of pyroelectric material (65), and a second part of the layer of two-dimensional layered material at least partly covers the foundation of the second sensor.

Abstract: A photodetector which comprises a measurement layer (15) and at least a first photoactive layer (11) which covers the measurement layer (15). The measurement layer (15) may be a transistor channel or a charge accumulation electrode. The conductivity type of the measurement layer is n-type, p-type or ambipolar and the first photoactive layer (11) exhibits intrinsic semiconductivity.

Abstract: A MESFET transistor on a horizontal substrate surface with at least one wiring layer on the substrate surface. The transistor comprises source, drain and gate electrodes which are at least partly covered by a semiconducting channel layer. The source, drain and gate electrodes optionally comprise interface contact materials for changing the junction type between each electrode and the channel. The interface between the source electrode and the channel is an ohmic junction, the interface between the drain electrode and the channel is an ohmic junction, and the interface between the gate electrode and the channel is a Schottky junction. The substrate is a CMOS substrate.

Abstract: A photosensitive field-effect transistor which can be configured to provide an electrical response when illuminated by electromagnetic radiation incident on the transistor. The field-effect transistor has a channel (13) made from a two-dimensional material and comprises a photoactive layer (22) which can be configured to donate charge carriers to the transistor channel (13) when electromagnetic radiation is absorbed in the photoactive layer (22). The photosensitive field-effect transistor comprises a top electrode (21) which is in contact with the photoactive layer on one or more contact areas which together form a contact pattern. With a suitably patterned top electrode (21), a voltage applied to the electrode can function as an electrical shutter which can switch the photosensitive field-effect transistor between a light-sensitive state and a light-immune state.

Abstract: A photosensitive field-effect transistor comprising a substrate with a source electrode, a drain electrode and a gate electrode. The transistor comprises a photoactive layer which at least partly covers the gate electrode, and a channel layer which covers the photoactive layer and at least partly covers both the source electrode and the drain electrode. The channel layer comprises a two-dimensional material whose conductivity is modulated by charge carriers transferred from the photoactive layer when electromagnetic radiation is absorbed in the photoactive layer.

Abstract: A photosensitive transistor or voltage-mode device which comprises a gate electrode, a layer of ambipolar two-dimensional material such as graphene and a layer of photoactive semiconducting material forms a junction with the ambipolar two-dimensional material. The photoactive semiconducting material and the ambipolar two-dimensional material are configured so that there is a non-screening gate voltage interval where an interface voltage at the junction between the photoactive semiconducting layer and the ambipolar two-dimensional material can be changed by applying to the gate electrode a gate voltage which falls within the non-screening gate voltage interval. The non-screening gate voltage interval comprises a flat-band gate voltage at which the interface voltage is zero. An electrical shutter can be operated at this gate voltage.

Abstract: A method comprising: providing a substrate comprising one or more electronic structures; providing a layer of perovskite overlaying the one or more electronic structures; coating a layer of photoresist material overlaying the layer of perovskite; aligning a mask with the one or more electronic structures and patterning the photoresist material; and using the same etchant to remove sections of the patterned photoresist material and the perovskite underneath the sections of the photoresist material.

Abstract: A photosensitive device that includes a conductive electrode, a dielectric layer, a sensing electrode composed of a two-dimensional layered material, and a photoactive layer which can be configured to absorb electromagnetic radiation. The photosensitive device also includes a single-ended measurement electrode for determining the electric potential of the sensing electrode.

Abstract: An apparatus comprising a pyroelectric layer, a two dimensional conductive channel and a floating gate. The pyroelectric layer is capacitively configured with respect to each of the two dimensional conductive channel and the floating gate. The floating gate comprises electrically connected first and second portions, the first portion is in thermal proximity to the first portion of the pyroelectric layer. The second portion is configured to overlie and gate flow of electrical charge through the two dimensional conductive channel by charge in the second portion of the floating gate. The first portion is functionalised to detect one or more proximal specific species. Such detection gives rise to heat flow to or from the thermally proximal pyroelectric layer to allow the pyroelectric layer to generate an electrical signal dependent upon one or more of the presence and amount of the specific detected species.

Abstract: An apparatus configured to alternate the application of first and second gate voltages to a gate electrode of a photodetector. A first change in electrical current is relative to a predetermined measurement of electrical current taken at the first gate voltage in the absence of incident electromagnetic radiation, and a second change in electrical current is relative to a predetermined measurement of electrical current taken at the second gate voltage in the absence of the incident electromagnetic radiation. The photodetector comprises a channel, and source and drain electrodes configured to enable flow of electrical current through the channel. Quantum dots are configured to generate charge carriers on exposure to the incident electromagnetic radiation. The gate electrode is configured to generate an electric field upon the application of a gate voltage thereto, and process the signal to at least partially remove any changes in electrical current which are attributed to noise.

Abstract: An apparatus comprising at least one pair of first and second photodetectors, each photodetector of the photodetector pair comprising a channel member, respective source and drain electrodes configured to enable a flow of electrical current through the channel member between the source and drain electrodes, and a plurality of quantum dots configured to generate electron-hole pairs on exposure to incident electromagnetic radiation to produce a detectable change in the electrical current flowing through the channel member, wherein the apparatus is configured such that the first and second photodetectors of the photodetector pair generate electron-hole pairs which produce an increase and decrease in electrical current through the channel members respectively, the combined change in electrical current of the pair of first and second photodetectors being indicative of one or more of the presence and magnitude of the incident electromagnetic radiation.

Abstract: An apparatus comprising: a plurality of sensors (501) arranged in an array (500), each sensor having a source electrode (504), a drain electrode (503), a gate electrode (505) and a channel, wherein the source electrode and drain electrode are elongate and the channel has a channel width defined by the longitudinal extent of the source and/or drain electrode and a channel length defined by the separation between the source and drain electrodes; a common conductive or semiconductive layer (506), which may be made of graphene, comprising the channels of the sensors (501) and arranged to extend over the plurality of sensors of the array and configured to be in electrical contact with at least the source electrode and the drain electrode of each sensor; and wherein the source electrode or drain electrode of each sensor forms a substantially continuous sensor perimeter at least along the channel width, which substantially encloses the other electrode of each sensor to inhibit the flow of charge carriers beyond the

Abstract: A photosensitive field-effect transistor configured to provide an electrical response when illuminated by electromagnetic radiation incident on the transistor. The photosensitive field-effect transistor comprises a layer of two-dimensional material which forms a horizontal transistor channel configured to transport current, and a horizontal semiconducting layer in contact with the transistor channel. The semiconducting layer comprises two or more assemblies of semiconducting material. If the two-dimensional material in the transistor channel has a high work function, the assemblies of semiconducting material are vertically stacked on the transistor channel in order of decreasing work function. If the two-dimensional material in the transistor channel has a low work function, the assemblies of semiconducting material are vertically stacked on the transistor channel in order of increasing work function.

Abstract: An apparatus comprises a layer of channel material, source and drain electrodes configured to enable a flow of electrical current through the channel material, and a layer of quantum dot material configured to generate electron-hole pairs on exposure to electromagnetic radiation to produce a detectable change in the electrical current indicative of one or more of the presence and magnitude of the electromagnetic radiation. The layer of quantum dot material is positioned between the channel material and a layer of conductive material. The layers of channel and conductive material have work functions such that respective built-in electric fields are created at the interfaces between the layer of quantum dot material and the channel and conductive material. The electric field at each interface acts in the same direction to promote separation of the electrons and holes of the electron-hole pairs to facilitate production of the detectable change in electrical current.

Abstract: A method and apparatus, the method comprising: forming at least two electrodes (23) on a release layer wherein the at least two electrodes are configured to enable a layer of two dimensional material (25) to be provided between the at least two electrodes; providing moldable polymer (27) overlaying the at least two electrodes; wherein the at least two electrodes and the moldable polymer form at least part of a planar surface (29).

Abstract: An apparatus and method, the apparatus comprising: at least one charged substrate (3); a channel of two dimensional material (5); and at least one floating electrode (7A-C) wherein the floating electrode comprises a first area (10A-C) adjacent the at least one charged substrate, a second area (11A-C) adjacent the channel of two dimensional material and a conductive interconnection (9A-C) between the first area and the second area wherein the first area is larger than the second area and wherein the at least one floating electrode is arranged to control the level of doping within the channel of two dimensional material.

Abstract: An apparatus comprising: pyroelectric material; an electric field sensor; a first conductive electrode comprising a first area adjacent the pyroelectric material; a second conductive electrode comprising a second area adjacent the electric field sensor; and a conductive interconnection between the first conductive electrode and the second conductive electrode, wherein the first area of the first conductive electrode is larger than the second area of the second conductive electrode.

Abstract: A method comprising: depositing a quantum dot solution onto a supporting substrate in a drop-wise manner to form one or more discrete droplets on a surface of the substrate, the quantum dot solution and discrete droplets comprising a plurality of quantum dots having primary ligands attached thereto to stabilize the quantum dots in solution; and depositing a ligand-exchange solution onto the one or more discrete droplets in a drop-wise manner to cause replacement of the primary ligands attached to the plurality of quantum dots with shorter-chain secondary ligands, replacement of the primary ligands with the secondary ligands allowing the plurality of quantum dots within each discrete droplet to become sufficiently close packed to facilitate charge transfer there between.

Abstract: An apparatus and method wherein the apparatus comprises: a sensing material configured to produce a non-random distribution of free charges in response to a parameter; an electric field sensor; a first conductive electrode comprising a first area overlapping the sensing material; an insulator provided between the first conductive electrode and the sensing material; a second electrode comprising a second area adjacent the electric field sensor; and a conductive interconnection between the first conductive electrode and the second conductive electrode.

Abstract: An apparatus and method wherein the apparatus comprises: a sensing material configured to produce a non-random distribution of free charges in response to a parameter; an electric field sensor; a first conductive electrode comprising a first area over-lapping the sensing material; an insulator provided between the first conductive electrode and the sensing material; a second electrode comprising a second area adjacent the electric field sensor; and a conductive interconnection between the first conductive electrode and the second conductive electrode.