Depletion region

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

Effect of Drain Doping Profile on Double-Gate Tunnel Field-Effect Transistor and its Influence on Device RF Performance

Abstract: In this paper, we have investigated the effect of drain doping profile on a double-gate tunnel field-effect transistor (DG-TFET) and its radio-frequency (RF) performances. Lateral asymmetric drain doping profile suppresses the ambipolar behavior, improves OFF-state current, reduces the gate-drain capacitance, and improves the RF performance. Further, placing the high-density layer in the channel near the source-channel junction, a reduction in the width of depletion region, improvement in ON-state current (I ON ), and subthreshold slope are analyzed for this asymmetric drain doping. However, it also improves many RF figures of merit for the DG-TFET. Furthermore, lateral asymmetric doping effects on RF performances are also checked for the various channel length. Therefore, this paper would be beneficial for a new generation of RF circuits and systems in a broad range of applications and operating frequencies covering RF spectrum. So, the RF figures of merit for the DG-TFET are analyzed in terms of transconductance (g m ), unit-gain cutoff frequency (f T ), maximum frequency of oscillation (f max ), and gain bandwidth product. For this, the RF figures of merit have been extracted from the V-parameter matrix generated by performing the small-signal ac analysis. Technology computer-aided design simulations have been performed by 2-D ATLAS, Silvaco International, Santa Clara, CA, USA.

Fundamental oscillations up to 200 GHz in resonant tunneling diodes and new estimates of their maximum oscillation frequency from stationary‐state tunneling theory

Abstract: Fundamental oscillations have been measured up to 200 GHz in resonant‐tunneling diodes at room temperature. Oscillations in the range 102–112 GHz were achieved with diodes mounted in a WR‐6 waveguide resonator, and the peak output power in this range was approximately 5 μW. The same diodes oscillated between 192 and 201 GHz and generated about 0.2 μW when mounted in a WR‐3 resonator. The estimated maximum oscillation frequency ( fmax) for these devices is 244 GHz, assuming the average drift velocity across the depletion layer to be 4×107 cm s−1. This estimate has been obtained from a new phenomenological theory of the negative differential conductance which accounts for the frequency‐dependent spreading resistance and transit‐time delay. The theory is also used to show that diodes having fmax exceeding 600 GHz are feasible simply by modifying the doping profile in the regions on either side of the double‐barrier structure.

Depletion layer thickness and Schottky type carrier injection at the interface between Pt electrodes and (Ba, Sr)TiO3 thin films

Abstract: The electrical conduction properties of rf sputter-deposited (Ba, Sr)TiO3 (BST) films on Pt and IrO2 electrodes and metalorganic chemical vapor deposited (MOCVD) BST films on a Pt electrode were investigated and a new energy band model that satisfactorily explains the observed leakage current characteristics and film thickness dependent dielectric properties is proposed. The BST and Pt junction constituted a blocking contact with interface potential barrier heights of 1.6–1.7 eV and 1.2 eV for the sputtered and MOCVD films, respectively. Schottky emission behavior was observed at measurement temperatures higher than 120 °C and tunneling related conduction behavior appeared below that temperature for a film thickness of 40 nm. A partial depletion model with a very thin (about 1 nm) layer devoid of space charge at the interface with the Pt electrode is proposed to explain the V1/2 dependent variation of ln(Jo) as well as the decreasing dielectric constant with decreasing film thickness.

Transparent semiconducting oxides: materials and devices

Abstract: Transparent conductive oxides (TCOs) are a well-known material class allowing Ohmic conduction. A large free carrier concentration in the 10 21 cm -3 range and high conductivity (beyond 10 4 S/cm) is feasible simultaneously with high transparency. Applications are manifold and include touch screens and front contacts for displays or solar cells. Transparent semiconducting oxides (TSO) are oxides with an intermediate free carrier concentration (typically 10 14 -10 18 cm -3 ) allowing the formation of depletion layers. We review recent results on TSO-based transistors and inverters. Most work has been reported on MISFETs. We show that MESFETs exhibit high performance and low voltage operation of oxide electronics. MESFET-based inverters offer superior performance compared to results reported for TSO MISFET-based circuits. Optical image of inverter based on thin film MESFETs with Mg 0.003 Zn 0.997 O channels (left) and experimental inverter characteristic for supply voltage of V DD = +2.0 V (right).

Electronic junction control in a nanotube-semiconductor Schottky junction solar cell.

Abstract: We exploit the low density of electronic states in single wall carbon nanotubes to demonstrate active, electronic modulation of their Fermi level offset relative to n-type silicon in a nanotube-Si (metal-semiconductor) Schottky junction solar cell. Electronic modulation of the Fermi level offset, the junction interface dipole and a field developed across the depletion layer modifies the built-in potential in the device and its power generation characteristics. As produced (before modulation) devices exhibit ∼8.5% power conversion efficiency (PCE). With active modulation the PCE is continuously and reversibly changed from 4 to 11%.