Depletion region

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

Drain avalanche breakdown in gallium arsenide MESFET's

Abstract: Avalanche breakdown in GaAs MESFET's simulated by two-dimensional (2-D) numerical calculation with a two-carrier model. The simulation involves electron-hole pair generation due to impact ionization and employs a simplified model of the surface depletion layer of GaAs. Gate-bias-dependent drain breakdown voltage is demonstrated. The effect of the surface depletion layer, drain-to-gate spacing and n/sup +/ layer under the drain contact upon the breakdown voltage is demonstrated. It is clarified that the surface depletion layer has a pronounced effect on the gate-bias dependence of the breakdown voltage. The breakdown mechanism is explained in terms of conductivity modulation in the semi-insulting substrate. >

An analytical model for the organic field-effect transistor in the depletion mode. Application to sexithiophene films and single crystals

Abstract: Organic field-effect transistors (OFETs) usually operate in the accumulation mode, where the biasing of the gate induces the charging of the insulator-semiconductor interface; the bias is negative in the most common case of p-type semiconductors. We show here that the application of a positive gate bias leads to the formation of a depletion layer, and a subsequent decrease of the drain current. We develop an analytical model for this depletion mode of the OFET. It is shown that measurements in the depletion mode give access to parameters such as the doping level and the density of trap levels. The model is applied to data obtained on sexithiophene (6T) film and single crystal OFETs. A substantial amount of traps is found in unsubstituted 6T, whereas the dihexyl substituted 6T is practically trap free. 6T single crystals are characterized by a very low doping level, which can be related to their very high purity. The possible use of the depletion mode to increase the on-off current ratio of OFETs is discussed.

Electrical measurements on n+‐GaAs‐undoped Ga0.6Al0.4 As‐n‐GaAs capacitors

Abstract: Current versus voltage (I‐V) and capacitance versus voltage (C‐V) characteristics have been measured for n+‐GaAs‐undoped Ga06Al04 As‐GaAs capacitors over a temperature range of 80–350 K At low temperatures the structure behaves like a semiconductor‐insulator‐semiconductor diode with interface barrier heights of 038 and 040 eV for the bottom and top interfaces, respectively The I‐V curves exhibit a rectifying behavior due to the formation of a substrate depletion layer, and the C‐V curves show the formation of the depletion layer under reverse bias as well as an accumulation layer containing >1012 electrons/cm2, in forward bias The C‐V curves agree closely with standard theory for SIS structures assuming Fermi–Dirac statistics for electrons in the accumulation layer, within an unaccounted‐for voltage shift of 016 V

Effect of metal electrodes on rubrene single-crystal transistors

Abstract: The authors herein have investigated the effect of the metal work function on the performance of rubrene single-crystal transistors using gold and calcium metal electrodes. The current-voltage characteristic is controlled by the metal work function, which offers the possibility of controlling the Schottky barrier height by the choice of the metal. In the process of the study of metal-rubrene contacts, the authors have realized an ambipolar transistor and a Schottky diode in an identical single-crystal device with asymmetric electrodes. These data provide direct evidence of the weak Fermi level pinning and formation of depletion layer on metal-rubrene contacts.