In a method of cleaning a substrate, a solution including a size-modification material is applied on a substrate, on which particles to be removed are disposed. Size-modified particles having larger size than the particles are generated, from the particles and the size-modification material. The size-modified particles are removed from the substrate.

Methods and materials for growing TMD materials on substrates and making semiconductor devices are described.

Devices converting light to electricity (such as solar cells or photodetectors) including a heavily-doped p-type a-SiC.sub.y:H and an i-Mg.sub.xCd.sub.1xTe/n-CdTe/NMg.sub.0.24Cd.sub.0.76Te double heterostructure (DH), with power conversion efficiency of as high as 17%, V.sub.oc as high as 1.096 V, and all operational characteristics being substantially better than those of monocrystalline solar cells known to-date. The a-SiC.sub.y:H layer is configured to enable high built-in potential while, at the same time, allowing the doped absorber to maintain a very long carry lifetime. In comparison, similar undoped CdTe/Mg.sub.xCd.sub.1xTe DH designs reveal a long carrier lifetime of 3.6 s and an interface recommendation velocity of 1.2 cm/s, which are lower than the record values reported for GaAs/Al.sub.0.5Ga.sub.0.5As (18 cm/s) and GaAs/Ga.sub.0.5In.sub.0.5P (1.5 cm/s) DHs.

A method is disclosed for making semiconductor films from a eutectic alloy comprising a metal and a semiconductor. Through heterogeneous nucleation said film is deposited at a deposition temperature on flexible substrates, such as glass. Specifically said film is vapor deposited at a fixed temperature in said deposition temperature where said deposition temperature is above a eutectic temperature of said eutectic alloy and below a temperature at which the substrate softens. Such films are nearly to entirely free of metal impurities and have widespread application in the manufacture and benefit of photovoltaic and display technologies.

A method is provided for making smooth crystalline semiconductor thin-films and hole and electron transport films for solar cells and other electronic devices. Such semiconductor films have an average roughness of 3.4 nm thus allowing for effective deposition of additional semiconductor film layers such as perovskites for tandem solar cell structures which require extremely smooth surfaces for high quality device fabrication.

The present invention proposes a method to form a gradient thin film using a spray pyrolysis technique. The method comprises providing a base substrate, preparing a spray aqueous solution by mixing at least two precursor compounds comprising at least two different elements and spraying the spray aqueous solution onto the base substrate. According to the present invention, the ratio of the concentration of the at least two different elements within the spray aqueous solution is varied while performing the method. In this way, a thin film having a gradient of elemental composition over its layer thickness may be formed.

This disclosure provides systems, methods, and apparatus related to photodetectors. In one aspect, a photodetector device comprises a substrate, a polycrystalline layer disposed on the substrate, and a first electrode and a second electrode disposed on the polycrystalline layer. The polycrystalline layer comprises nanograins with grain boundaries between the nanograins. The nanograins comprise a semiconductor material. A doping element comprising a halogen is segregated at the grain boundaries. A length of the polycrystalline layer is between and separating the first electrode and the second electrode.

Methods for growing and using large-grain templates are provided. According to an aspect of the invention, a method includes depositing a small-grain layer of a semiconductor material; treating the small-grain layer such that the small-grain layer becomes a large-grain layer; and growing an epitaxial layer of the semiconductor material on the large-grain layer. A ratio of an average grain size of the small-grain layer to a thickness of the small-grain layer is less than 1.0, and a ratio of an average grain size of the large-grain layer to a thickness of the large-grain layer is greater than 1.5.

The present application discloses a zinc oxide-crystalline silicon laminated solar cell and a preparation method thereof, relates to the technical field of solar cells, and aims to solve the technical problem of low photoelectric conversion rate of existing solar cells. The zinc oxide-crystalline silicon laminated solar cell includes: a P-type silicon substrate layer; a front surface of the P-type silicon substrate layer being sequentially formed with, from bottom to top, a diffusion layer, an N-type zinc oxide layer, a first passivation layer, and a first antireflection layer; wherein the N-type zinc oxide layer is made of tetrapod-like N-type zinc oxide whisker powder as a raw material; and a back surface of the P-type silicon substrate layer being sequentially formed with, from top to bottom, a second passivation layer and a second antireflection layer; and an electrode, the electrode including a front electrode and a back electrode.

The present invention provides a heat treatment method, particularly a heat treatment method in which a protective layer is directly applied onto a precursor to ensure that the precursor on each portion of the substrate is treated based on substantially the same conditions so that the quality of the prepared product layer is improved. The method of the present invention comprises: (1) providing a substrate; (2) applying a precursor onto the surface of the substrate; (3) covering the precursor-applied substrate with a protective layer to bring the substrate and the protective layer into direct contact; (4) placing the substrate obtained from step (3) into a heat chamber for heat treatment; and (5) removing the protective layer. A product prepared by said heat treatment method is also provided.