Temperature Dependence Of Drift Mobility Research Articles

Temperature dependence of the c-axis drift mobility in 4H–SiC

The electrical characteristics of 4H–SiC Schottky diodes were performed in the temperature range 80–700 K, in order to determine the temperature dependence of the drift mobility. At room temperature, a value of 724 cm 2/(V s) was found, which decreased to 48.6 cm 2/(V s) at 700 K. In the temperature range 200–700 K, a dependence of the mobility as T −3 was determined, that can be correlated to the presence of material defects.

Transient behavior of the polarity-reversal current in a nematic liquid-crystal device

We report on observations of transient behavior of currents induced by the polarity reversal of a dc voltage applied across a nematic liquid-crystal cell. The curve of the time-evolved transient current reveals two peaks for the external voltage larger than a characteristic value. The temperature dependence of drift mobility of ion carriers implies that both the first and second peaks are caused by the director orientation in the bulk.

Carrier transport in porous silicon

Carrier transport in porous silicon layers has been studied by the time-of-flight method in the strong injection mode at temperatures T=290–350 K and electric field strengths F=(1.5–7)×104 V cm−1. The electron and hole drift mobilities μe≈2×10−3 cm2 V−1 s−1 and μh≈6×10−4 cm2 V−1 s−1 were obtained at T=292 K and F=4×104 V cm−1. An exponential temperature dependence of drift mobility with activation energy of ∼0.38 and ∼0.41 eV for, respectively, electrons and holes was established. It is shown that the type of time dependences of the photocurrent associated with carrier drift and the superlinear dependence of the transit time on the reciprocal of the voltage applied to a sample allow use of the concept of space-charge-limited currents under the conditions of anomalous dispersive transport. The experimental data are accounted for in terms of the model of transport controlled by carrier trapping into localized states with energy distribution near the conduction and valence band edges described by an exponential function with a characteristic energy of ∼0.03 eV.

Temperature Dependence of Drift Mobility in Bismuth Germanium Oxide and Bismuth Silicon Oxide

Temperature Dependence of Drift Mobility in Bismuth Germanium Oxide and Bismuth Silicon Oxide

Transient photocurrent of a-Si:H in weak electron phonon coupoling

A weak electron phonon coupling for the multiphonon process was applied to the multiple trapping model in order to overcome difficulties in the model. Compared with the conventional multiple trapping model, electron occupation probability is reduced and the demarcation level is shallow. The photocurrent has power law decay and the experimental temperature dependence of drift mobility can be explained.

Temperature dependence of drift mobility in the presence of trap-recombination centers

The effect of trap-recombination centers on the temperature dependence of the chargecarrier drift mobility μg in semiconductors is investigated both theoretically and experimentally. The temperature dependence μg(T) becomes steeper than the temperature dependence of the microscopic mobility μ(T) in the temperature range where Ed=Et ± 2κT (Ed is the demarcation level; Et is the level at which the centers occur). The dependence μg(T) is measured experimentally in CdS from the temperature dependence of the acoustic current. The experiments agree with the theoretical calculations.

Drift mobility of holes in phenanthrene single crystals

The temperature dependence of drift mobilities of holes in single crystals of phenanthrene was measured in the range 203–353°K in three crystallographic directions. Below the anomaly temperature of 72°C, the mobility temperature dependences are consistent with the Munn and Siebrand slow-phonon hopping process in the b direction and the Munn and Siebrand slow-phonon coherent mode in the a and c′ directions. The drift mobility temperature dependences in crystals that have been cooled through the anomaly temperature in the presence of illumination and an electric field are consistent with the model of Spielberg et al., in which the hindered vibration of the 4,5 hydrogens introduces a new degree of freedom above 72°C.

Drift mobility of holes and electrons in perdeuterated anthracene single crystals

The temperature dependence of drift mobilities in perdeuterated anthracene was measured in the range 260–400°K in three crystal directions. Shallow trapping analysis of the temperature dependence allowed determination of the trap-free drift mobilities along the a, b, and c′ crystal axes. Room temperature trap-free mobilities agreed well with those found in normal anthracene, except for the mobility of electrons along the c′ crystal axis which was found to decrease about 10% upon deuteration. Various models for charge carrier transport in anthracene were examined, and it was found that the c′-electron mobility in deuterated anthracene is consistent with the Munn and Siebrand slow-phonon hopping mode while all other components are consistent with the Munn and Siebrand slow-phonon coherent mode.

The Temperature Dependence of Drift Mobility in Germanium

The Temperature Dependence of Drift Mobility in Germanium