Drift velocity oscillations in n-GaAs at 77 K

Abstract

Electron relaxtion after an instantaneous application of a dc electric field ranging from 10 V/cm to 1 kV/cm is studied numerically by a many‐particle Monte Carlo method. The model takes into account polar optical, acoustic, and impurity scattering in the nonparabolic central valley. In the limited range of doping, electric field, and temperature the electron mean energy and drift velocity oscillate. The oscillation frequency is nearly proportional to the applied electric field (approximately 35 GHz at 60 V/cm). The oscillations are associated with a shuttle‐type electron motion in the Debye sphere of k‐space they are not heavely damped if the electron runaway is favoured inside and restrained outside the Debye sphere.

Hot-electron transient and terahertz oscillations in graphene

“…This type of oscillation has already been predicted in GaAs, 8 and indirectly observed in slightly n-doped InSb. 9 However, their manifestation in these materials is different in several respects: First, owing to the carrier parabolic energy-momentum dispersion, the oscillation periodicity in GaAs is instead given by τ GaAs = 2m * hω GaAs OP /eF .…”

“…7 The coherent aspect of this process, that is, the coherent acceleration of the carrier distribution function followed by quasi-instantaneous carrier relaxation by OP's at high energy, is expected to produce oscillations of the carrier velocity with a periodicity given by τ gr = hω OP /eF v F ∼ 1 ps (Ref. 8) for F ∼ 2 kV/cm, that is, in the terahertz range.…”

“…9 However, their manifestation in these materials is different in several respects: First, owing to the carrier parabolic energy-momentum dispersion, the oscillation periodicity in GaAs is instead given by τ GaAs = 2m * hω GaAs OP /eF . 8,10,11 Second, and more importantly, in III-V semiconductors, the oscillation onset is restricted by two conflicting conditions: On the one hand, the low value of the OP energy (hω OP ∼ 0.04 eV) (Ref. 12) is comparable to the thermal broadening of the carrier distribution at room temperature so that the back-and-forth motion of the distribution between the optic phonon and the zero-point energy is immediately damped.…”

Full-Band Monte Carlo Simulation of HgCdTe APDs

“…The electron drift velocity characteristic in CdTe as a function of temperature and electric field was measured by the transient-charge technique by Canali et al 12 Borsari and coworkers 13 performed Monte Carlo calculations of electron transport in CdTe to investigate the negative differential mobility of this material, which was attributed to the randomizing effect of intervalley scattering rather than to the population of lower-mobility valleys. 13 Monte Carlo calculations of hot-electron transient behavior in CdTe were presented by Matulionis et al 14 Scarce information is available on the impact ionization properties of HgCdTe alloys. Gelmont and Kim 15 derived impact ionization and Auger recombination rates within the framework of the six-band Kane model.…”

A 2D Full-Band Monte Carlo Study of HgCdTe-Based Avalanche Photodiodes

“…Despite this significant potential, scarce information is available on the transport properties of CdTe and HgCdTe alloys, especially at high field strength. Monte Carlo simulations of electron transport in CdTe were presented by Borsari and Jacoboni, 6 and Matulionis et al 7 and Yoo and Kwack 8 studied the low-field electron mobility in n-type HgCdTe using a relaxation time approximation method. Monte Carlo simulations of HgCdTe avalanche photodiodes based on an analytical band model have been presented by at least two groups.…”