Minority electron mobilities in GaAs, In0.53Ga0.47As, and GaAs0.50Sb0.50 calculated within an ensemble Monte Carlo model

Tea, Eric; Aniel, F.

doi:10.1063/1.3533963

Cited by 23 publications

(23 citation statements)

References 54 publications

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“…Indeed, the presence of an extra valley close to the conduction band minimum has several implications, as seen in GaAsSb for example. 45 First, electrons in the satellite valley virtually have less kinetic energy than in the main valley, because of the 0.2 eV offset. This translates into overall smaller electron velocities than if the material only had a single conduction valley.…”

Section: --The Satellite Valleymentioning

confidence: 99%

Charge carrier transport and lifetimes in n-type and p-type phosphorene as 2D device active materials: an ab initio study

Tea

Hin

2016

Phys. Chem. Chem. Phys.

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In this work, we provide a detailed analysis of phosphorene's performance as an n-type and p-type active material. This study is based on first principles calculations of the phosphorene electronic structure, and the resulting electron and hole scattering rates and lifetimes. Emphasis is put on extreme regimes commonly found in semiconductor devices, i.e. high electric fields and heavy doping, where impact ionization and Auger recombination can occur. We found that electron-initiated impact ionization is weaker than the hole-initiated process, when compared to carrier-phonon interaction rates, suggesting resilience to impact ionization initiated breakdown. Moreover, calculated minority electron lifetimes are limited by radiative recombination only, not by Auger processes, suggesting that phosphorene could achieve good quantum efficiencies in optoelectronic devices. The provided scattering rates and lifetimes are critical input data for the modeling and understanding of phosphorene-based device physics.

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Section: --The Satellite Valleymentioning

confidence: 99%

Charge carrier transport and lifetimes in n-type and p-type phosphorene as 2D device active materials: an ab initio study

Tea

Hin

2016

Phys. Chem. Chem. Phys.

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“…This conclusion is also supported by theoretical considerations at the high doping levels used here. 7,8 Considering only scattering by electrical charges, the momentum relaxation time hs m i ¼ l e m Ã =q, where m Ã is the effective mass, is written as an average over electron kinetic energy e of the energy-resolved time s m ðeÞ. One can write that s m ðeÞ ¼ aðT L ; T e Þe p , where the exponent p depends on the efficiency of the screening by holes 21 and where, as found above, the dependence of aðT L ; T e Þ on T L should be weaker than that on T e .…”

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confidence: 98%

Central role of electronic temperature for photoelectron charge and spin mobilities in p+-GaAs

Cadiz

Paget

Rowe

et al. 2015

Applied Physics Letters

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The charge and spin mobilities of minority photoelectrons in p þ -GaAs are determined by monitoring the effect of an electric field on the spatial profiles of the luminescence and of its polarization. By using electric fields to increase the photoelectron temperature T e without significantly changing the hole or lattice temperatures, the charge and spin mobilities are shown to be principally dependent on T e . For T e > 70 K, both the charge and spin mobilities vary as T À1:3 e , while at lower temperatures this changes to an even more rapid T À4:3 e law. This finding suggests that current theoretical models based on degeneracy of majority carriers cannot fully explain the observed temperature dependence of minority carrier mobility. V C 2015 AIP Publishing LLC.Understanding the mechanisms which limit the minority carrier charge mobility l e and spin mobility l s in semiconductors is necessary for the correct design of bipolar charge and spin devices. The electron mobility in p-type GaAs features a completely different temperature dependence than that of majority electrons in n-GaAs for a similar doping level. 1-3 A number of possible reasons for this have been discussed in the literature, including carrier freezeout at high hole concentrations, 4,5 screening of ionized impurities, 6 and increasing hole degeneracy as temperature is lowered. 7 Here, we experimentally measure the minority electron mobility as a function of lattice temperature T L and electronic temperature T e of p þ -GaAs. The ability to change T e without changing T L using an applied electric field is used to demonstrate that the charge and spin mobilities are primarily determined by T e . The sample consists of a 3 lm thick, carbon doped material ðN A ¼ 10 18 cm À3 Þ. A 100 nm thick GaInP epilayer between the semi-insulating substrate and the active layer ensures that recombination at the interface is negligible. As shown in Fig. 1(a), a Hall bar was photolithographically etched into the active layer. Fig. 1(b) shows the dependence as a function of the lattice temperature (T L ) of the resistivity, the majority hole concentration, and the mobility. The density of ionized acceptors is only weakly temperature dependent for this doping level since the impurity band and the valence band are merged into a continuum of states. 4,5 The hole mobility at room temperature, l h ¼ 202 cm 2 V À1 s À1 , as well as its $T 1=2 L temperature dependence below 100 K are in good agreement with previous reports on similarly doped GaAs. 5,9,10 Spin-polarized photoelectrons were generated by a tightly focussed circularly polarized CW laser excitation (1/e half width of 0.6 lm, energy 1.59 eV unless otherwise stated) in a setup described elsewhere. 11 A maximum excitation power of 0.01 mW produces a non degenerate photoelectron concentration of $5 Â 10 14 cm À3 in the steady state. The temperature T e was monitored from the high energy tail of the luminescence spectrum. This spectrum was obtained using a multimode optical fiber placed in the image plane FIG. 1. (a) S...

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“…To accurately account for degeneracy effects, our modelization also features the Pauli Exclusion Principle for all bands, and LOPC. 18 In order to take into consideration the phonon bottleneck effect, carrier-polar LO phonon scattering rates have to be calculated all along the simulation using the real-time LO phonon population N LO , which can be out of thermal equilibrium. The carrier-LOPCM scattering rates are calculated in the same way using the following expression…”

Section: A Charge Carriers Emcmentioning

confidence: 99%

“…We present here a coupling of two dedicated Ensemble Monte Carlo solvers (EMC), one for charge carriers 18 and one for phonons, 19 exchanging data to simultaneously account for the accurate evolutions of both the carriers and phonons populations. Thus both systems are treated thoroughly by solving their respective BTE without relying on the common RTA for phonon populations.…”

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confidence: 99%

Hot carriers relaxation in highly excited polar semiconductors: Hot phonons versus phonon–plasmon coupling

Tea

Hamzeh

Aniel

2011

Journal of Applied Physics

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We present a study of the photo-excited charge carriers relaxation dynamics in polar semiconductors comparing calculations to pump probe experiments. Hot carrier densities in the 10 18 cm À3 range can easily be photo-generated using moderately intense optical excitations. This can lead to known phenomena, namely, hot phonon populations and the coupling of polar optical phonons with plasmon modes. However, these two phenomena can affect the hot carriers relaxation and have never been examined together. This is a problem for the theoretical study of future Hot Carrier Solar Cells, where the conditions allow both of these phenomena to occur. The charge carriers dynamics and the coupling of polar optical phonons with plasmon modes are treated by a Full Band Ensemble Monte Carlo simulation code featuring a self-consistent dielectric function. To take into consideration hot phonon populations and the subsequent phonon bottleneck for the carriers relaxation, the charge carriers simulation code is coupled to a phonon dedicated Ensemble Monte Carlo code. This enables for the first time an accurate study of both the charge carriers and phonon systems dynamics, the latter being most of the time overly simplified in previous studies. The present work explores to which extent the two aforementioned phenomena affect the photo-generated charge carriers relaxation in GaAs and can be easily adapted to other polar semiconductors.

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Minority electron mobilities in GaAs, In0.53Ga0.47As, and GaAs0.50Sb0.50 calculated within an ensemble Monte Carlo model

Cited by 23 publications

References 54 publications

Charge carrier transport and lifetimes in n-type and p-type phosphorene as 2D device active materials: an ab initio study

Charge carrier transport and lifetimes in n-type and p-type phosphorene as 2D device active materials: an ab initio study

Central role of electronic temperature for photoelectron charge and spin mobilities in p+-GaAs

Hot carriers relaxation in highly excited polar semiconductors: Hot phonons versus phonon–plasmon coupling

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