Investigation of the parameters of a two-dimensional electron gas in InGaN/GaN quantum wells by the method of terahertz plasmon resonance

A new approach to determining the parameters of a two-dimensional electron gas in InGaN/GaN quantum wells is proposed. It is based on the method of terahertz spectroscopy with time resolution, within the framework of which the terahertz 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 terahertz 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 terahertz spectra, the effect of renormalization of the effective mass of two-dimensional electron gas, as well as phase modulation near the frequencies of plasmon resonances with an increase in the temperature of the sample from 90 to 170 K, was found. The proposed method is non-contact and can be used in a wide temperature range.