High-frequency conductivity and temperature dependence of electron effective mass in AlGaN/GaN heterostructures

Abstract

We present calculations of frequency and wavevector dispersion of conductivity of two-dimensional electrons confined in AlGaN/GaN heterostructures at the arbitrary level of the degeneracy and the presence of strongly inelastic scattering mechanism by the optical phonons. We found that the high-frequency conductivity deviates from that of the standard Drude–Lorentz model and changes significantly at elevated temperature. The results were applied for simulation of the spectral characteristics of the grating-based plasmonic structure for wide temperature range. We found that thermal activation of the inelastic scattering leads to significant red-shift of the plasmon resonances. This facilitates refinement of interpretation of experimental results published in series of recent papers. We concluded that for AlGaN/GaN heterostructures, the electron effective mass changes in narrower diapason of 0.22me,…,0.26me, when temperature varies from 77 to 300 K. We suggest that found peculiarities of the high-frequency conductivity and its spatial dispersion are of a general character and can be important for high-frequency and high power devices based on AlGaN/GaN heterostructures.