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.     

Frequency and temperature dependences of capacitance-voltage characteristics of InGaN/GaN light-emitting structures with multiple quantum wells

A frequency dependence of capacitance-voltage (C–V) characteristics in multiple quantum well InGaN/GaN heterostructures in the range of 60 Hz-5 MHz is investigated at temperatures from 77 to 300 K. It is found that temperature lowering and test frequency increase lead to the similar changes in obtained apparent carrier distributions. It is shown that commonly used conditions for capacitance-voltage profiling of InGaN/GaN LEDs correspond to an intermediate case between low- and high-frequency capacitance approximations. At all temperatures investigated, the edge low-frequency capacitance-voltage profiles are experimentally reached and found to be identical. The process of attainment of equilibrium of the charges in the active region is most likely determined by tunneling of the carriers through the barriers.     

Studying Magnetic Diodes with a GaMnAs Layer Formed by Pulsed Laser Deposition

Semiconductors - A new design for diode heterostructures with (Ga, Mn)As ferromagnetic layers is experimentally investigated. The diode structures are fabricated using a combination of...