Depletion region

About: Depletion region is a research topic. Over the lifetime, 9393 publications have been published within this topic receiving 145633 citations.

Voltage variable capacitor having amorphous dielectric film

Abstract: A semiconductor device (10), comprising a semiconductor substrate (12) having a layer of semiconductor material (14) deposited, coated or grown epitaxially as a single crystal or polysilicon on the surface of the substrate. The layer of material is also a semiconductor material, having a higher resistivity than the substrate it is deposited on. A dielectric layer (16) of a metal oxide is formed on the high resistivity layer (14), which is then covered with an amorphous layer (18) of a metal oxide dielectric. Zirconium titanate may be used as a metal oxide dielectric layer. A metal electrode (20) is formed on the amorphous layer (18) to form a Metal Insulator Semiconductor device. In an alternative configuration, the amorphous layer (18) may instead be placed between the high resistivity layer (14) and the dielectric layer (16), or a second amorphous layer (22) may be added between the high resistivity layer and the dielectric layer. When the device is electrically energized, a depletion region is formed in the high resistivity layer, creating a voltage variable capacitor.

Measurement of Nonlinear Polarization of KTaO3 using Schottky Diodes

Abstract: Capacitance vs bias voltage data are presented for Au–KTaO3 surface barrier Schottky diodes. Substantial deviations from the normal Schottky capacitance relationship have been observed and attributed to a field‐dependent dielectric constant in the depletion layer. From the capacitance data obtained at room temperature, e vs E and P vs E curves have been calculated for KTaO3 and found to be consistent with previous measurements made using conventional techniques at 4.2°K.

Undoped-emitter InP/InGaAs HBTs for high-speed and low-power applications

Abstract: Scaling down the lateral emitter dimension is an effective way to reduce the power dissipation of HBT ICs. Various authors have demonstrated submicrometer HBTs operating at >100 GHz with submilliampere current. On the other hand, there have been few reports on vertical layer structures optimized for low-current operation. At low current, the dominant delay time of HBTs is the emitter charging time. Thus, it is essential to reduce the emitter junction capacitance by increasing the thickness of the emitter depletion layer. In this paper, we propose an undoped-emitter structure for InP-based HBTs and investigate its impact on low-power applications.

Study of photocurrent generation in InP nanowire-based p + -i-n + photodetectors

Abstract: We report on electrical and optical properties of p+-i-n+ photodetectors/solar cells based on square millimeter arrays of InP nanowires (NWs) grown on InP substrates The study includes a sample series where the p+-segment length was varied between 0 and 250 nm, as well as solar cells with 93% efficiency with similar design The electrical data for all devices display clear rectifying behavior with an ideality factor between 18 and 25 at 300 K From spectrally resolved photocurrent measurements, we conclude that the photocurrent generation process depends strongly on the p+-segment length Without a p+-segment, photogenerated carriers funneled from the substrate into the NWs contribute strongly to the photocurrent Adding a p+-segment decouples the substrate and shifts the depletion region, and collection of photogenerated carriers, to the NWs, in agreement with theoretical modeling In optimized solar cells, clear spectral signatures of interband transitions in the zinc blende and wurtzite InP layers of the mixed-phase i-segments are observed Complementary electroluminescence, transmission electron microscopy (TEM), as well as measurements of the dependence of the photocurrent on angle of incidence and polarization, support our interpretations

Paving the way to nanoionics: atomic origin of barriers for ionic transport through interfaces.

Abstract: The blocking of ion transport at interfaces strongly limits the performance of electrochemical nanodevices for energy applications. The barrier is believed to arise from space-charge regions generated by mobile ions by analogy to semiconductor junctions. Here we show that something different is at play by studying ion transport in a bicrystal of yttria (9% mol) stabilized zirconia (YSZ), an emblematic oxide ion conductor. Aberration-corrected scanning transmission electron microscopy (STEM) provides structure and composition at atomic resolution, with the sensitivity to directly reveal the oxygen ion profile. We find that Y segregates to the grain boundary at Zr sites, together with a depletion of oxygen that is confined to a small length scale of around 0.5 nm. Contrary to the main thesis of the space-charge model, there exists no evidence of a long-range O vacancy depletion layer. Combining ion transport measurements across a single grain boundary by nanoscale electrochemical strain microscopy (ESM), broadband dielectric spectroscopy measurements and density functional calculations, we show that grain-boundary-induced electronic states act as acceptors, resulting in a negatively charged core. Besides the possible effect of the modified chemical bonding, this negative charge gives rise to an additional barrier for ion transport at the grain boundary.