5 results about "Modulation doping" patented technology

The application discloses an electrically controlled InAs / GaAs quantum dot van der Waals heterojunction SESAM structure, which comprises a semi-insulating GaAs substrate, a reflection layer and an absorption layer, wherein the reflection layer is located on the upper layer of the semi-insulating GaAs substrate, the reflection layer is composed of a plurality of cycles of Si-doped GaAs / Al 0.98 Ga 0.02 As distributed Bragg reflector at the bottom; the middle part of the absorption layer is an absorption zone of the SESAM, the absorption zone is composed of inserting an InAs quantum dot layer (QD) with a thickness of 2.9 molecular layers between a 1nm-thick InGaAs bottom buffer layer and a 6nm-thick InAs / GaAs / InGaAs short-period superlattice cover layer, and 50nm-thick modulated Si-doped GaAs layers are respectively added to the upper and lower parts of the absorption layer to form a double two-dimensional electron gas structure.

The invention provides a modulation-doped aluminum nitride / diamond heterojunction material and a preparation method, and belongs to the technical field of semiconductors, and the preparation method comprises the following steps: preparing a hydrogen terminal layer on a diamond substrate to form a hydrogen terminal diamond substrate; growing an intrinsic aluminum nitride layer on the hydrogen terminal layer in an oriented manner; and modulating and growing a magnesium-doped aluminum nitride functional layer on the intrinsic aluminum nitride layer to form a hierarchical interface charge transport channel. According to the preparation method of the modulation-doped aluminum nitride / diamond heterojunction material provided by the invention, directional regulation and control of interface carriers are realized through hierarchical structural design of the surface of the hydrogen terminal diamond in combination with precise process control of pulse laser deposition, the carrier mobility and charge transport efficiency of the heterojunction are remarkably improved, and the performance of the material is improved. The aluminum nitride / diamond heterojunction material with high electrical characteristics is obtained, and the technical contradiction that process feasibility and electrical property optimization cannot be considered in the prior art is solved.

The invention discloses a tungsten-doped ZrNiSn thermoelectric composite material as well as a preparation method and application thereof, ZrNiSn is taken as a matrix, ZrNiSn powder and W nanoparticles are uniformly mixed, and the ZrNiSn-W thermoelectric composite material is obtained through rapid densification treatment. Through the combination of tungsten modulation doping and an energy filtering effect, the bottleneck of half-Heusler material PF-zT coupling optimization is broken through, and the PF and zT values of the thermoelectric material are significantly improved; according to the invention, the hafnium element is abandoned, a large-scale and low-cost solution is provided for large-scale application of the half-Heusler thermoelectric material, the raw material cost is reduced by more than 95%, and an economical solution is provided for large-scale deployment of the thermoelectric material.

N-channel modulation-doped field-effect transistors (N-MODFETs) in which a two-dimensional electron gas (2DEG) channel is formed in intrinsic diamond are provided. The n-MODFETs can be made using bandgap engineering and a transfer and grafting process to couple intrinsic diamond, which has a very high electron mobility, with a highly n-type doped aluminum gallium nitride (AlGaN) alloy as an electron donor material to realize a high-cutoff frequency (fT) MODFET for radiofrequency (RF) electronics applications.

This invention discloses a deep ultraviolet LED with a modulation-doped multiple quantum well structure and its fabrication method. The deep ultraviolet LED comprises a sapphire substrate, an intrinsic AlN layer, an N-type AlGaN layer, a current spreading layer, a modulation-doped multiple quantum well layer, an electron blocking layer, a P-type AlGaN injection layer, and a P-type GaN contact layer, which are sequentially stacked. On the one hand, this invention prevents Si diffusion into the quantum well layer by placing undoped material near the quantum well layer in the modulation quantum barrier layer; on the other hand, the doping concentration of the doped quantum barrier layer in the modulation-doped multiple quantum well layer gradually decreases along the direction from the N-type AlGaN layer to the P-type AlGaN injection layer, thereby limiting electron overflow, enhancing hole migration to neighboring quantum wells, improving carrier injection efficiency, and thus improving the luminous efficiency of the deep ultraviolet LED device.