Certain embodiments of the present invention may be directed to a transistor structure. The transistor structure may include a semiconductor substrate. The semiconductor substrate may include a drift region, a collector region, an emitter region, and a lightly-doped/undoped region. The lightly-doped/undoped region may be lightly-doped and/or undoped. The transistor structure may also include a heterostructure. The heterostructure forms a heterojunction with the lightly-doped/undoped region. The transistor structure may also include a collector terminal. The collector terminal is in contact with the collector region. The transistor structure may also include a gate terminal. The gate terminal is in contact with the heterostructure. The transistor structure may also include an emitter terminal. The emitter terminal is in contact with the lightly-doped/undoped region and the emitter region.

A photodetector comprising an optical waveguide structure comprising at least three stripes spaced from one another such that a slot is present between each two adjacent stripes of the at least three stripes. A graphene absorption layer is provided over or underneath the at least three stripes. There is an electrode for each stripe, over or underneath the graphene absorption layer. The photodetector is configured such that two adjacent electrodes are biased using opposite polarities to create a p-n junction effect in a portion of the graphene absorption layer. In particular the portion of the graphene absorption layer is located over or underneath each respective slot between said each two adjacent stripes.

Certain embodiments of the present invention may be directed to a transistor structure. The transistor structure may include a semiconductor substrate. The semiconductor substrate may include a drift region, a collector region, an emitter region, and a lightly-doped/undoped region. The lightly-doped/undoped region may be lightly-doped and/or undoped. The transistor structure may also include a heterostructure. The heterostructure forms a heterojunction with the lightly-doped/undoped region. The transistor structure may also include a collector terminal. The collector terminal is in contact with the collector region. The transistor structure may also include a gate terminal. The gate terminal is in contact with the heterostructure. The transistor structure may also include an emitter terminal. The emitter terminal is in contact with the lightly-doped/undoped region and the emitter region.

Solar cells, absorber structures, back contact structures, and methods of making the same are described. The solar cells and absorber structures include a pseudomorphically strained electron reflector layer.

A photodetector comprising an optical waveguide structure comprising at least three stripes spaced from one another such that a slot is present between each two adjacent stripes of the at least three stripes. A graphene absorption layer is provided over or underneath the at least three stripes. There is an electrode for each stripe, over or underneath the graphene absorption layer. The photodetector is configured such that two adjacent electrodes are biased using opposite polarities to create a p-n junction effect in a portion of the graphene absorption layer. In particular the portion of the graphene absorption layer is located over or underneath each respective slot between said each two adjacent stripes.

An infrared detection film includes a gate electrode, a gate insulating layer, a majority-carrier channel layer, at least one drain terminal, at least one source terminal, and a photovoltaic semiconductor layer. The gate insulating layer is formed on the gate electrode. The majority-carrier channel layer is formed on the gate insulating layer. Each of the at least one drain terminal and the at least one source terminal is disposed on the majority-carrier channel layer and is spaced apart from the gate electrode. The photovoltaic semiconductor layer is disposed on an exposed portion of the majority-carrier channel layer exposed between the at least one drain terminal and the at least one source terminal.

An infrared detection film includes a gate electrode, a gate insulating layer, a majority-carrier channel layer, at least one drain terminal, at least one source terminal, and a photovoltaic semiconductor layer. The gate insulating layer is formed on the gate electrode. The majority-carrier channel layer is formed on the gate insulating layer. Each of the at least one drain terminal and the at least one source terminal is disposed on the majority-carrier channel layer and is spaced apart from the gate electrode. The photovoltaic semiconductor layer is disposed on an exposed portion of the majority-carrier channel layer exposed between the at least one drain terminal and the at least one source terminal.

Solar cells, absorber structures, back contact structures, and methods of making the same are described. The solar cells and absorber structures include a pseudomorphically strained electron reflector layer.

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.

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.