Mobility of electrons in a AlGaN/GaN QW: Effect of temperature, applied field, surface roughness and well width

Abstract

We study the dependence of low field mobility on various parameters such as well width and interface roughness for a two-dimensional electron gas confined to a AlGaN/GaN quantum well as a function of temperature. The potential profile, the energy levels, electron concentrations and wave functions for each level are found from the self-consistent numerical solution of Schrödinger and Poisson equations for the quantum well. Then the scattering rates for electrons due to acoustic phonons, optical phonons and interface roughness are obtained using the self consistently calculated wave functions. Ensemble Monte Carlo technique is used to find the drift velocities of the two-dimensional electrons along the interface. The mobility of two-dimensional electrons is extracted from these data. Electron transport properties of bulk GaN is also studied in order to compare the two and three-dimensional mobility values. It is seen that electron mobilities upto 40 × 10 3 cm 2 /Vs can be obtained in a 2DEG confined to an AlGaN/GaN hetero interface. The results of simulation are compared with experimental findings and it is seen that the agreement between simulation and experiments in two dimensions is very satisfactory.

Transport and mobility properties of wurtzite InN and GaN

“…It can be noted that there is a significant increase in peak velocity when the new parameters are used. decreases [33]. The peak velocity of GaN at 300 K is 2.75 × 10 7 cm/s at 140 kV/cm field, whereas that at 600 K is 2.25 × 10 7 cm/s at 170 kV/cm.…”

“…The scattering mechanisms mentioned in the previous section are considered in the ensemble Monte Carlo [27,33] simulation of electron transport in WZ InN and GaN. There are three sets of parameters used for InN ensemble Monte Carlo simulations.…”

“…2 fitted to a third-degree polynomial similar to Ref. [33]. The drift mobility determined from the linear part of the velocity versus field curve below 5 kV/cm was used in Refs.…”

Transport and Mobility Properties of Bulk Indium Nitride (InN) and a Two-Dimensional Electron Gas in an InGaN/GaN Quantum Well

“…We have previously shown that the peak velocity increases while the field at which it is attained decreases as the temperature decreases for GaN. 37 For the traditional material parameter values of effective mass 0.11m 0 , gap energy 1.89 eV, and nonparabolicity value of 0.419 eV -1 resulting from the Kane model, a highest velocity value of 3.7 · 10 7 cm/s is attained in three dimensions under the given conditions for InN at 300 K at a field value of about 62 kV/cm, as seen in Fig. 3.…”

Steady-State Electron Transport and Low-Field Mobility of Wurtzite Bulk ZnO and Zn1−x Mg x O

“…13,14 Low-field electron mobility as a function of temperature and ionized impurity concentration is extracted from the slope of the linear part of the velocity-field curves. Acoustic phonon, polar optical phonon, intervalley (equivalent and nonequivalent), ionized impurity, and alloy scatterings are the scattering processes used to obtain the low-field mobilities.…”