Provided are a solar cell and a light emitting device with low leakage current and low cost, using ZnO fine particles. A p-type ZnO layer (p-type layer) (14) made primarily of p-type ZnO fine particles (931) is formed. P-side electrodes (16) are formed at a plurality of regions on the p-type layer (14). A thin insulating layer (18) is formed between an n-type layer (13) and the p-type layer (14). In the insulating layer (18), openings are formed at regions A each not overlapping the p-side electrodes (16) and being apart from them in a plan view. In the configuration, by thus making the p-side electrodes (16) apart from the regions A, the length of a current path in the p-type layer (14) can be made substantially larger than the layer thickness. Accordingly, even when n-type ZnO fine particles (932) are incorporated in the p-type layer (14), it is possible to interpose some of the p-type ZnO fine particles (931) along a leakage current path caused by the incorporation, and thereby cut off the current path.

An optical sensor includes a graphene layer, a first electrode and a second electrode that are connected to the graphene layer, and an enhancement layer. The enhancement layer is disposed below the graphene layer to enhance the intensity of an optical electric field by surface plasmon resonance. The first electrode and the second electrode are arranged parallel to a first direction. The intensity of the optical electric field enhanced by the enhancement layer is greater on a first electrode side than on a second electrode side with respect to a centerline in the first direction of the graphene layer.

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 semiconductor device includes element regions which each include a first region of a first conductivity type, a second region of the first conductivity type on the first region and having a higher impurity concentration than that of the first region, a third region of a second conductivity type on the second region. The second region is between the first and third regions in a first direction. A first insulating portion surrounds each element region in a first plane. A fourth region of the first conductivity type surrounds each element region and the first insulating portion in the first plane. The fourth region has a higher impurity concentration than that of the first region. A quenching structure is above a part of the fourth region in the first direction and electrically connected to the third region.

A semiconductor photodiode. The semiconductor photodiode including: an input waveguide, arranged to receive an optical signal at a first port and provide the optical signal from the second port; a photodiode waveguide, arranged to receive the optical signal from the second port of the input waveguide, and at least partially convert the optical signal into an electrical signal; and an electro-static defence component, located adjacent to the photodiode waveguide. The electro-static defence component and the photodiode waveguide are electrically connected in parallel.

A disclosed semiconductor photodetector includes a first semiconductor layer having a first refractive index and a first band gap; a second semiconductor layer formed on the first semiconductor layer, the second semiconductor layer having a second refractive index and a second band gap; a first electrode; and a second electrode. The second refractive index is greater than the first refractive index, and the second band gap is smaller than the first band gap. The first semiconductor layer includes a p-type first region, an n-type second region, and a non-conductive third region between the first region and the second region. The second semiconductor layer includes a p-type fourth region in ohmic contact with the first electrode, an n-type fifth region in ohmic contact with the second electrode, and a non-conductive sixth region between the fourth region and the fifth region.

A single-photon detection pixel includes a substrate, a first well provided in the substrate, a pair of heavily doped regions provided on the first well, and a contact provided between the pair of heavily doped regions, wherein the substrate and the pair of heavily doped regions have a first conductivity type, and the first well and the contact have a second conductivity type that is different from the first conductivity type.

Techniques for enhancing the absorption of photons in semiconductors with the use of microstructures are described. The microstructures, such as pillars and/or holes, effectively increase the effective absorption length resulting in a greater absorption of the photons. Using microstructures for absorption enhancement for silicon photodiodes and silicon avalanche photodiodes can result in bandwidths in excess of 10 Gb/s at photons with wavelengths of 850 nm, and with quantum efficiencies of approximately 90% or more.

In one example, a sensor comprises a photovoltaic device. The photovoltaic device comprises a core having a shape that is at least partially spherical, an absorber disposed over the core, and a transparent conductor disposed over the absorber. Other examples and related methods are also disclosed herein.

A photon avalanche diode includes a semiconductor body having a first side and a second side opposite the first side, a primary doped region of a first conductivity type at the first side of the semiconductor body, a primary doped region of a second conductivity type opposite the first conductivity type at the second side of the semiconductor body, an enhancement region of the second conductivity type below and adjoining the primary doped region of the first conductivity type, the enhancement region forming an active pn-junction with the primary doped region of the first conductivity type, and a collection region of the first conductivity type interposed between the enhancement region and the primary doped region of the second conductivity type and configured to transport a photocarrier generated in the collection region or the primary doped region of the second conductivity type towards the enhancement region.