Bias-dependent time-resolved photoluminescence spectroscopy on 265 nm AlGaN-based LEDs on AlN substrates

Abstract

Abstract Time-resolved photoluminescence spectroscopy under an external bias is performed on 265 nm AlGaN-based LEDs on AlN substrates. The bias dependences of the photoluminescence wavelength, intensity, and decay time are observed. Our experimental results indicate that the built-in electric field has the opposite sign as the polarization-induced electric field in the quantum-well layers. These results agree with the first-principles calculations but are contrary to a previous experimental study. Additionally, thermionic and tunneling escape processes from the quantum-well layers play a minor role in the non-unity current injection efficiency at room temperature under a low injection (non-droop) regime.