A semiconductor device includes a substrate, a two-dimensional (2D) material layer formed on the substrate and having a first region and a second region adjacent to the first region, and a source electrode and a drain electrode provided to be respectively in contact with the first region and the second region of the 2D material layer, the second region of the 2D material layer including an oxygen adsorption material layer in which oxygen is adsorbed on a surface of the second region.

A Ge-on-Si photodetector constructed without doping or contacting Germanium by metal is described. Despite the simplified fabrication process, the device has responsivity of 1.24 A/W, corresponding to 99.2% quantum efficiency. Dark current is 40 nA at 4 V reverse bias. 3-dB bandwidth is 30 GHz.

An organic solar cell device is provided, including a first electrode, a photoactive layer, a hole transport layer, and a second electrode that are stacked successively. The photoactive layer includes an electron receptor material and an electron donor material. The electron receptor material is graphene nitride that forms a foamy film on the first electrode and has a three-dimensional network structure. A part of the electron donor material permeates into the graphene nitride, and a part of the electron donor material is enriched on a side of the hole transport layer to form an electron donor enriched layer.

Provided are a nanostructure and an optical device including the nanostructure. The nanostructure is formed on a two-dimensional material layer such as graphene and includes nanopatterns having different shapes. The nanopatterns may include a first nanopattern and a second nanopattern and may be spherical; cube-shaped; or poly-pyramid-shaped, including a triangular pyramid shape; or polygonal pillar-shaped.

Compound semiconductors, expressed by the following formula: Bi.sub.1-xM.sub.xCu.sub.wO.sub.a-yQ1.sub.yTe.sub.b-zQ2.sub.z. Here, M is at least one element selected from the group consisting of Ba, Sr, Ca, Mg, Cs, K, Na, Cd, Hg, Sn, Pb, Eu, Sm, Mn, Ga, In, Tl, As and Sb; Q1 and Q2 are at least one element selected from the group consisting of S, Se, As and Sb; x, y, z, w, a, and b are 0x<1, 0<w1, 0.2<a<4, 0y<4, 0.2<b<4 and 0z<4. These compound semiconductors may be used for various applications such as solar cells or thermoelectric conversion elements, where they may replace compound semiconductors in common use, or be used along with compound semiconductors in common use.

Photovoltaic devices such as solar cells, hybrid solar cell-batteries, and other such devices may include an active layer disposed between two electrodes. The active layer may have perovskite material and other material such as mesoporous material, interfacial layers, thin-coat interfacial layers, and combinations thereof. The perovskite material may be photoactive. The perovskite material may be disposed between two or more other materials in the photovoltaic device. Inclusion of these materials in various arrangements within an active layer of a photovoltaic device may improve device performance. Other materials may be included to further improve device performance, such as, for example: additional perovskites, and additional interfacial layers.

Processes for controlling the growth and thickness of two-dimensional transition metal dichalcogenides are provided. The process modifies an insulator substrate surface with an electron or ion beam to create charged areas on the substrate surface. The treated surface allows for hydroxylation of the charged species which serves as nucleation sites for the seed particles during chemical vapor deposition that promotes growth of thin layers of transition metal dichalcogenides.

HD color video using monochromatic CMOS image sensors integrated in a 3D package is provided. An example 3DIC package for color video includes a beam splitter to partition received light of an image stream into multiple light outputs. Multiple monochromatic CMOS image sensors are each coupled to one of the multiple light outputs to sense a monochromatic image stream at a respective component wavelength of the received light. Each monochromatic CMOS image sensor is specially constructed, doped, controlled, and tuned to its respective wavelength of light. A parallel processing integrator or interposer chip heterogeneously combines the respective monochromatic image streams into a full-spectrum color video stream, including parallel processing of an infrared or ultraviolet stream. The parallel processing of the monochromatic image streams provides reconstruction to HD or 4K HD color video at low light levels. Parallel processing to one interposer chip also enhances speed, spatial resolution, sensitivity, low light performance, and color reconstruction.

Disclosed is a solar cell including a semiconductor substrate including a semiconductor material, a tunneling layer disposed over one surface of the semiconductor substrate, a first conductive area and a second conductive area disposed over the tunneling layer and having opposite conductive types, and an electrode including a first electrode electrically connected to the first conductive area and a second electrode electrically connected to the second conductive area. At least one of the first conductive area and the second conductive area is configured as a metal compound layer.

A method of detecting a change in current is provided which includes irradiating light on at least one photoelectric conversion material layer, and detecting an increased change in current generated in the photoelectric conversion material layer. A photoelectric conversion apparatus is also provided and includes a photoelectric conversion element including a photoelectric conversion material layer, and a current detection circuit electrically connected to the photoelectric conversion element. In the photoelectric conversion apparatus, the current detection circuit detects an increased change in current generated in the photoelectric conversion material layer.