Analysis of the temperature dependence of the capacitance-voltage characteristics of InGaN/GaN multiple quantum well light-emitting structures

The capacitance-voltage characteristics and frequency dependences of the capacitance and conductance of InGaN/GaN multiple quantum well light-emitting structures are studied in the frequency range of 60 Hz-5 MHz and the temperature range of 77–300 K. It is shown that carrier relaxation in quantum wells can be described by two emission processes, i.e., the thermally activated one and with the power-law temperature dependence of the emission rate. It is also shown that one or several quantum wells in typical InGaN/GaN-based light-emitting structures can remain filled with electrons even at comparatively high reverse biases. This makes it possible to explain the depth shift of the apparent carrier concentration profiles, obtained from the capacitance-voltage characteristics, with decreasing temperature.