New photoelectrical properties of InN: Interband spectra and fast kinetics of positive and negative photoconductivity of InN

Using a Fourier transform spectrometer and a pulsed laser, we study spectra and kinetics of positive and negative photoconductivity (PC) along with other types of photoexcitation spectra of n-type InN epilayers with Hall concentrations from 3 × 1017 to 5 × 1019 cm−3 at room and low temperatures. The PC, absorption, and photoluminescence spectra of the investigated InN samples correspond to a degenerate homogenous direct band semiconductor. In contrast to previous works, we observed positive and negative PC with relaxation times in the nano- and microsecond ranges. The sign of PC depends on the temperature and the equilibrium carrier concentration.