Calculated Current-voltage Characteristics Research Articles

Tunneling through AlAs barriers: Γ–X transfer current

We have investigated Γ–X intervalley transfer tunneling by measuring currents at low temperature in a series of single AlAs barrier samples grown on GaAs substrates. The transfer occurs at AlAs-GaAs interfaces and is intrinsic because the translational symmetry is broken in the growth direction of the epitaxial layered structures. Calculated current-voltage characteristics employing a simple effective mass model which includes Γ–X transfer at heterointerfaces agree reasonably well with experiments, while calculations assuming only the Γ-band potential predict currents several orders of magnitude lower than experiments.

An analytical DC model for the modulation-doped field-effect transistor

A novel analytical dc model for the MODFET device is introduced. The model is based on the approximate equations obtained for the 2DEG charge density under the equilibrium and current conduction conditions. The electron charge mobility and velocity-electric field characteristics in the device channel are modeled using semi-empirical expressions in order to obtain the current-voltage drain characteristics that are related directly to the physical parameters of the device structure and its ambient temperature. The calculated current-voltage characteristics using the developed model compare well with the experimental results obtained for a low-noise microwave MODFET at different temperatures. It is believed that due to the model simplicity, it is suitable for implementation in the existing microwave CAD packages.

GaSb Schottky diodes for infrared detectors

GaSb Schottky barrier photodiodes are shown to have quantum efficiency higher than 35 percent over a broad band of infra-red light wavelength shorter than 1.6 µm. Theoretical calculations of current voltage characteristics including tunneling current are compared with the experiment and it is suggested that surface leakage current, tunneling current, and avalanche breakdown, respectively, dominate the reverse characteristics with increasing voltage. Epitaxial growth of an n-type layer with carrier density 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">15</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> and suitable surface passivation are key technologies for the application of this material to infra-red detectors.

Effect of electrical-conductivity variations on the characteristics of arc discharges

Algebraically calculated current-voltage characteristics of arc discharges are obtained with a canal model for planar and cylindrical arcs and electrical conductivity given as a power of the heat-flux potential. For slower than linear variation, the current-voltage characteristic has a distinct minimum, whereas for faster than linear variation the arc electric field tends to zero as current increases without limit.

Zur theorie der photofeldemission aus metallen

Expressions for the field emission current density at illumination of the emitter are derived in dependence on the photon energy. Calculated current-voltage characteristics for tungsten show that the change of the emission current per photon is some orders of magnitude smaller than the usual field emission current density. A modulated-light technique is necessary for the experimental investigation of the photofield emission effect. The illumination intensity must be high enough to overcome the noise of the field emission current.