7 results about "Drift velocity" patented technology

This invention discloses a plasma local current measurement device and method based on optical methods, belonging to the field of optical measurement technology. The device includes: a high-energy pulsed laser, a beam splitter, a photodiode for triggering an ICCD camera, a beam sampling mirror for providing optical signals to the photodiode, a focusing lens for focusing the high-energy pulsed laser, a pulsed power device for generating Z-pinch plasma, a beam collector, an achromatic lens for collecting scattered light, a reflective grating spectrometer, an ICCD camera, and a Mach-Zehnder interferometer. Electron density distribution, electron temperature, ion temperature, plasma velocity, and relative electron-ion drift velocity can be simultaneously obtained through plasma interference fringe images and Thomson scattering spectra. The local current at the measurement point is obtained by multiplying the electron density, electron charge, and relative electron-ion drift velocity at the measurement point.

This invention proposes a velocity-controlled graphene non-reciprocal near-field thermal radiation measurement device and method, belonging to the fields of nanoscale thermal management and photonics technology. A first graphene plate and a second graphene plate are placed parallel to each other in a high-vacuum cavity, with a nanoscale vacuum gap between them. A macroscopic displacement platform is connected to the first graphene plate to control its macroscopic movement velocity along the interface direction. A precision DC power supply is connected to the second graphene plate to inject current to induce microscopic drift velocity of its internal charge carriers. A high-precision temperature sensor is in contact with both graphene plates to monitor their temperature. A near-field heat flux meter is located on the back side of the second graphene plate to measure the radiative heat flux passing through the gap. A calculation and control unit is connected to the macroscopic displacement platform, the precision DC power supply, the high-precision temperature sensor, and the near-field heat flux meter to coordinate and control the velocity parameters and collect and process heat flux data.

A high-current drift transistor (HSDT) with low losses is to be realized by having electrons with energies E <EF-kBT (EF=Fermi-Energie, kB=Boltzmann-Konstante, T=Temperatur) eines völlig gefüllten Leitungsbands eines zweidimensionalen Elektronengases (2DEG) der Dimensionen Lx·Ly in der x-y-Ebene einem Magnetfeld Bz und elektrischen Feldern Ex und Ey ausgesetzt werden, was sie alle auf eine Driftgeschwindigkeit vD in der x-y-Ebene zwingen soll. Der resultierende elektrische Driftstrom kann sehr groß werden, da er widerstandlos ist, denn die beteiligten Elektronen können nicht durch Streuung an Fehlstellen, Verunreinigungen oder Phononen gestört werden, da alle möglichen Endzustände dieser Prozesse durch andere Elektronen besetzt sind. Damit kann der HSDT sehr große elektrische Leistungen im kW-Bereich steuern.

The invention discloses a quick-response organic photoelectric detector with a planar heterojunction structure. The quick-response organic photoelectric detector sequentially comprises a transparent substrate, an anode, a hole transport layer, an electron transport layer, a hole barrier layer and a metal cathode, the material of the hole transport layer is MCBP or TCTA; the thickness of the hole transport layer is 75-85 nm; the anode is made of indium tin oxide, a conductive polymer or metal Au; the hole blocking layer is made of BCP; the thickness of the hole blocking layer is 8-12nm; a potential barrier formed by the hole transport layer and the anode reduces injection of an external circuit under high bias voltage; and meanwhile, the hole barrier layer reduces injection at one side of the cathode. The MCBP or TCTA is used as a hole transport layer material, and the BCP is used as a hole barrier layer material, so that the dark current of the device is inhibited, the electric field intensity in the device and the drift speed of carriers are improved, the detector can stably work under high bias voltage, and the response speed of the device can be improved.

The present invention discloses a mercury cadmium telluride detector chip with a high saturation threshold and a preparation method thereof. The mercury cadmium telluride detector chip includes a substrate, an epoxy resin adhesive, a p-type photosensitive layer, an n-type ion implantation layer, a passivation layer, an n-type electrode layer, and a p-type electrode layer. The p-type photosensitive layer is a Hg 1‑ x Cd x Te component gradient layer, which sequentially includes a Cd component linearly gradient Hg 1‑x Cd x Te layer and a Cd component non-linearly gradient Hg 1‑x Cd x Te layer. The Cd component x gradually changes from high to low from the upper surface of the Cd component non-linearly gradient Hg 1‑x Cd x Te layer to the lower surface of the Cd component linearly gradient Hg 1‑x Cd x Te layer. The n-type ion implantation layer of the chip of the present invention is formed in the Cd component non-linearly gradient Hg 1‑x Cd x Te layer. The strong built-in electric field introduced by the gradient bandgap improves the drift velocity of holes, reduces the accumulation of holes in the space charge region, simultaneously inhibits the diffusion motion of carriers in the p region, reduces the collection efficiency of pn junctions for photo-generated electrons in the p region, reduces the carrier concentration in the space charge region, increases the saturation threshold of the chip, and enables operation at room temperature with zero bias voltage.

The invention discloses a detector radiation resistance reinforcement design method based on electric field distribution regulation and control, and the method comprises the steps: building an electric field distribution model through optimizing a groove structure, and regulating and controlling the electric field intensity E; calculating Vd through a carrier drift speed Vd calculation formula based on E; a bottom angle with the curvature radius being R is arranged at the bottom of the groove, and Epeak is calculated through an initial peak electric field Epeak calculation formula of the bottom corner point of the groove; p + ions are injected into the P + ion injection layer from the side wall of the groove, R is optimized by changing the doping concentration of the P + ions injected into the side wall of the groove, and Epeak is calculated in combination with a peak electric field Epeak calculation formula of corner points at the bottom of the groove after optimization; constructing an irradiation resistance evaluation model based on the Epeak and the Epeak to calculate an irradiation resistance factor RHF; regulating and controlling Vbr through a breakdown voltage Vbr lifting model constructed by changing the thickness of the N layers and combining Epeak; and representing the radiation resistance characteristic of the detector based on Vd, RHF and Vbr. According to the method, electric field regulation and control are combined with structure optimization, so that the reliability and the stability of the detector in an irradiation environment are improved.

A photoelectric detector with an inverted p-GaN / AlGaN / n-GaN structure is characterized in that a conventional p-GaN / AlGaN / n-GaN structure is inverted to form the inverted p-GaN / AlGaN / n-GaN structure, and the inverted p-GaN / AlGaN / n-GaN structure comprises an n-type GaN layer, namely, n-GaN, an Al < x > Ga < 1-x > N barrier layer and a p-type GaN layer, namely, p-GaN, which are sequentially stacked from top to bottom; according to the invention, the n-GaN is doped with the p-GaN, so that the ultraviolet light directly enters the n-GaN, the absorption or interference of the p-GaN and the passivation layer on the ultraviolet light in a conventional structure is avoided, the absorption efficiency of the ultraviolet light is improved, higher sensitivity and gain can be obtained, and meanwhile, due to high electron mobility and high saturation drift speed in the GaN, the detector has a very high response speed, so that the sensitivity and the gain of the detector are improved. And the detector is simple in process and low in cost, and can meet the requirements of the field of ultraviolet detection, especially the field of weak light detection.