9 results about "Band engineering" patented technology

The invention discloses a visible-infrared image fusion detector structure and a preparation method thereof. The detector structure comprises a substrate, a visible light absorption layer, an infrared light absorption layer, a metal electrode layer and a protection layer from bottom to top. The structure monolithic integrates a visible light detector and an infrared detector. P-type and N-type doping of the same semiconductor material is realized by regulating and controlling the number of atomic layers (or the thickness of the material) by utilizing the self-doping effect of the number of atomic layers of the two-dimensional semiconductor, so that regulation and control of an electric field built in a heterojunction and a photon-generated carrier transport process are realized through energy band engineering. In combination with a differential mechanism of a spatial domain current signal, detection and imaging of an independent visible band (450-700 nanometers) and an independent infrared band (1.5-4 microns) are realized in a single device. The planar heterojunction detector does not need a complex optical system and a bias circuit, the preparation process is simple, and a novel device design scheme is provided for visible-infrared image fusion detection.

The application provides a two-dimensional Janus material and an energy level parameter prediction method and device thereof, a mother body and a Janus material crystal structure are constructed into a graph structure, after improving node / edge features, local information is aggregated through a graph attention network with edge embedding, global attention mechanism is used to obtain graph-level embedding, then difference features are obtained by subtracting the two embeddings, and a multilayer perception machine is used to predict a conduction band bottom offset, a valence band top offset and a vacuum energy level difference, in addition, a multi-task weighted loss optimization model is used. The application uses differential learning of the mother body-Janus pairing, reduces the calculation cost, improves the prediction accuracy and generalization ability, can realize high-throughput screening, and supports Janus material energy band engineering design.

The invention provides a two-dimensional CsxRb (1-x) PbBr3 single crystal nanosheet and a preparation method thereof. Aiming at the problems of volatility difference of CsBr and RbBr and mismatch of Cs < + > and Rb < + > ion radiuses, the invention develops a chemical vapor deposition process with partition temperature cooperative control and multi-parameter optimization, and realizes controllable preparation of high-quality single crystal nanosheets in a full-component range for the first time. The structure has a regular square shape, the transverse size reaches tens of microns, and the thickness is several nanometers. Under laser excitation, the PL spectrum of the sample proves the continuous adjustability of the components and band gaps. All the alloy nanosheets show excellent single-peak emission characteristics, the photoluminescence peak position of the alloy nanosheets can be continuously tuned to 525 nm (green light) of CsPbBr3 from 447 nm (blue light) of RbPbBr3, and it is indicated that the synthesized all-component alloy has extremely high crystal quality. The two-dimensional structure with precise and controllable energy band engineering shows a wide application prospect in the fields of basic physical research and high-performance nano optoelectronic devices.

The invention relates to a photoelectric detector, a manufacturing method thereof and a spectrograph, and the photoelectric detector comprises a P-type semiconductor substrate which is used for generating an electron-hole pair under the action of measured light; the wide bandgap oxide layer covers the surface of the P-type semiconductor substrate, the thickness of the wide bandgap oxide layer is 1-20 nm, the valence band top energy level of the wide bandgap oxide layer is at least lower than the valence band top energy level of the P-type semiconductor substrate material by 1.5 eV, and the wide bandgap oxide layer is used as a heterointerface barrier layer; and the Schottky contact layer covers the surface of the wide band gap oxide layer. The photoelectric detector disclosed by the invention adopts a vertical structure of the P-type semiconductor substrate / the wide bandgap oxide layer / the Schottky contact layer, and realizes efficient suppression (-1nA magnitude) and effective collection of dark current while simplifying the device structure (without photoetching) by utilizing the unipolar barrier characteristic and heterojunction energy band engineering of the wide bandgap oxide layer.

The invention discloses a method for growing an MAPbBr3 single crystal through a mixed solvent and a gamma ray detector, and relates to the technical field of semiconductor material preparation and radiation detection.The method comprises the steps that a precursor solution is prepared through the mixed solvent of DMF and DMSO, and the low-defect-density and large-size MAPbBr3 single crystal is obtained through growth at the precisely-controlled heating rate through a temperature inversion crystallization technology; according to a gamma ray detector constructed based on the single crystal, a Bi / MAPbBr3 / Au asymmetric electrode structure is adopted, and surface polishing treatment and protection ring design are combined, so that dark current and noise are remarkably reduced; according to the method, the dissolution-crystallization thermodynamic and dynamic behaviors of MAPbBr3 are regulated and controlled through the DMF-DMSO mixed solvent, controllable growth of low-defect-density single crystals is achieved, and the high-performance room-temperature gamma ray detector is constructed in combination with surface defect repair and asymmetric electrode energy band engineering.

The application discloses a kind of based on heterostructure energy band engineering regulation and control negative photoconductive device, belong to optoelectronic device and semiconductor hetero integration field, including substrate, wide band gap photosensitive material layer, narrow band gap two-dimensional channel material layer, electrode;Two material layers contact and form heterojunction and pass energy band structure and Fermi level matching design, so that the device is in no light, two-dimensional channel material layer forms stable conductive channel under the action of source-drain electrode bias voltage, and the device presents normal conduction characteristic;Under illumination, photosensitive material layer absorbs photon and generates the photo-generated carrier opposite to two-dimensional channel material layer multi-subtype, and the photo-generated carrier is injected into two-dimensional channel material layer under the driving of interface built-in electric field, and is combined with two-dimensional channel material layer multi-subtype, reduces two-dimensional channel material layer carrier concentration and current, realizes negative photoconductive effect.The device structure is simple, repeatability is strong, process compatible, suitable for sensing storage integration and brain-like computing system.

The invention discloses a colloidal quantum dot-based photoelectrochemical dual-band detection device and a preparation method thereof, and belongs to the technical field of photoelectric detection. Wherein the photoelectrochemical device adopts a PIN type photoanode structure and is composed of a transparent substrate, a transparent conductive anode, an N type colloidal quantum dot visible light absorption layer, an intrinsic type colloidal quantum dot visible light absorption layer, a P type colloidal quantum dot infrared absorption layer and a hole consumption layer. Wherein the colloidal quantum dot absorption layer comprises visible light wave band response type quantum dots (such as CdSe) and short wave infrared wave band response type quantum dots (such as AgSe), and dual-wave band independent detection is achieved through energy band engineering. And an electrochemical solution medium adopts a high-concentration solution, so that a solid-liquid interface double-charge layer can be improved, a consumption path of photo-anode hole sacrificial agent molecules is optimized, and the dual-band detection rate is improved.

The invention provides a two-dimensional Janus material and an energy level parameter prediction method and device thereof, and the method comprises the steps: constructing a matrix and Janus material crystal structure into a graph structure, improving the node / edge features, carrying out the aggregation of local information and a global attention mechanism through an edge-embedded graph attention network to obtain graph-level embedding, carrying out the subtraction of the two types of embedding, obtaining a difference feature, and carrying out the prediction of the energy level parameters of the two-dimensional Janus material. The conduction band bottom offset, the price band top offset and the vacuum energy level difference are predicted through multiple tasks of a multi-layer perceptron, and in addition, the model is optimized through multi-task weighted loss. According to the method, differential learning of parent-Janus pairing is utilized, the calculation cost is reduced, the prediction precision and generalization ability are improved, high-throughput screening can be achieved, and Janus material energy band engineering design is supported.

The invention mainly researches and utilizes a post-selenylation method to improve the energy band arrangement of the antimony sulfide solar cell. Firstly, proper raw materials and solvents are selected, antimony potassium tartrate hemihydrate and sodium thiosulfate pentahydrate are used as precursor materials of Sb and S, and an antimony sulfide thin film is prepared through a hydrothermal deposition method. And carrying out energy band engineering treatment on the surface of the antimony sulfide film. The influence of energy band engineering processing on the aspects of thin film morphology, crystal structure, band gap, energy level position and the like is researched. Under the condition of energy band engineering treatment, the crystallinity of the thin film is improved, crystal grains are increased, the morphology of the antimony sulfide thin film is improved, the energy level orientation is good, compared with a control group treated by the energy band engineering, the photoelectric conversion efficiency is remarkably improved, and no other impurities are introduced into the final absorption layer thin film.