Relaxation time, mobility, and effective mass of 2DEG in InGaN/GaN quantum wells according to terahertz plasmon resonance data

A new approach to determining the parameters of a two-dimensional electron gas (2DEG) in InGaN/GaN quantum wells is proposed. It is based on the method of terahertz (THz) spectroscopy with time resolution, within the framework of which the THz frequencies of two-dimensional plasmon resonances excited in the studied samples of InGaN/AlGaN/GaN heterostructures by femtosecond laser pulses at a wavelength of 797 nm were recorded. Oscillating behavior of the output THz radiation power with minima in the frequency range 1 - 5 THz is shown, which is associated with the excitation of plasmon oscillations in a two-dimensional electron gas localized in an InGaN/GaN quantum well. During the processing of THz spectra, the effect of renormalization of the effective mass of 2DEG, as well as phase modulation near the frequencies of plasmon resonances with an increase in the temperature of the sample from 90K to 170K, was found. The proposed method is non-contact and can be used in a wide temperature range.