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Hall Effect Characterization of Nanowires
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Olof Hultin, Kristian Storm, Lars Samuelson
The current in a semiconductor can be described by drift and diffusion. Drift current is due to the electrons’ response to an electric field, whereas diffusion current is caused by diffusion of carriers between areas with different carrier densities. The drift and diffusion currents for electrons can be written as Jn=qnμE+μkTdndr
Optical Receivers
Published in Abdul Al-Azzawi, Photonics, 2017
The three fundamental sources of leakage current are: Generation-recombination (g−r) current: Arises from the generation and recombination of electron-hole pairs in the diode depletion region. The g−r current dominates the leakage current at low temperature.Diffusion current: Arises from the diffusion of the minority carriers, toward or away from the junction, in the diode neutral region. In the case of P+−n junction with the intrinsic region width larger than the hole diffusion length, the intrinsic region alone may be considered. Then diffusion current dominates the leakage current at high temperature.Tunneling current: Refers to the band-to-band tunneling in the presence of high electric fields. A high field reduces the effective band gap barrier, allowing carriers to cross the band gap.
Optical Receivers
Published in Abdul Al-Azzawi, Fibre Optics, 2017
The three fundamental sources of leakage current are: Generation-recombination (g−r) current: Arises from the generation and recombination of electron-hole pairs in the diode depletion region. The g−r current dominates the leakage current at low temperature.Diffusion current: Arises from the diffusion of the minority carriers, toward or away from the junction, in the diode neutral region. In the case of P− -n junction with the intrinsic region width larger than the hole diffusion length, the intrinsic region alone may be considered. Then diffusion current dominates the leakage current at high temperature.Tunneling current: Refers to the band-to-band tunneling in the presence of high electric fields. A high field reduces the effective band gap barrier, allowing carriers to cross the band gap.
Impact of neutron irradiation on electronic carrier transport properties in Ga2O3 and comparison with proton irradiation effects
Published in Radiation Effects and Defects in Solids, 2023
Jonathan Lee, Andrew C. Silverman, Elena Flitsiyan, Minghan Xian, Fan Ren, S. J. Pearton
The trap thermal activation energy of luminescence can be determined by measuring the intensity as a function of temperature. The following relation describes CL intensity, ICL, as a function of temperature where A and B are scaling constants, Ea is thermal activation energy, kB is the Boltzmann constant, and T is temperature. Equilibrium CL intensity is proportional to the rate of carrier recombination, and inversely proportional to the minority carrier lifetime. Under continuous stationary electron beam excitation, local traps begin to become occupied and alter the CL intensity. This implies a time dependence on the intensity of CL under a continuous electron beam excitation. Diffusion current occurs when carriers migrate from areas of high to low concentration. The minority carrier diffusion length, L, in semiconductors describes the statistical distance an excited carrier will travel in a given direction before recombination. The diffusion length can be related to lifetime, τ, by where D is the diffusion coefficient, which is related to the carrier’s mobility, µ, by the Einstein’s relation
Effects of temperature and applied strain on corrosion of X80 pipeline steel in chloride solutions
Published in Corrosion Engineering, Science and Technology, 2018
W. Yuan, F. Huang, J. Liu, Q. Hu, Y. Frank Cheng
Figure 6 shows the potentiodynamic polarisation curves of X80 pipeline steel in 3.5 wt-% NaCl solution containing 7 mg L−1 DO at various temperatures. The anodic branches show that the steel is in an active dissolution state, with the anodic current density increasing with temperature. The cathodic branches show obvious limiting diffusion currents due to the reduction reaction of DO. The limiting diffusion current density (id) is approximately independent of temperature. When the cathodic potential is sufficiently negative, hydrogen evolution dominates the cathodic reduction reaction, as clearly observed in the cathodic branches of the measured polarisation curves. As the temperature increases, the cathodic reduction current density increases, indicating the increasing hydrogen evolution kinetics. This is attributed to the reduced energy barrier for hydrogen evolution and accelerating cathodic reaction at elevated temperatures.