Well-To-Well Non-Uniformity In Ingan/Gan Multiple Quantum Wells Characterized By Capacitance-Voltage Measurement With Additional Laser Illumination

We experimentally investigated well-to-well non-uniformity in InGaN/GaN multiple quantum well (MQW) structures by using capacitance-voltage measurements with additional laser illumination. By varying the illuminating power of the resonant excitation, well-to-well non-uniformity through the MQWs was clearly revealed. The quantum wells (QWs) close to the n-GaN side show higher carrier accumulations and larger position shift as the excitation power is increased, relative to the p-side QWs. Both results were attributed to the existence of stronger piezoelectric fields in the n-side QWs induced by subsequent partial relaxation of strain through the MQWs. (C) 2012 American Institute of Physics. [doi:10.1063/1.3685717]