Analysis of the physical mechanisms responsible for leakage current and reverse-bias luminescence in green LEDs

With this paper we present an analysis of the physical processes responsible for leakage current conduction and reverse-bias luminescence in InGaN-based green Light-Emitting Diodes (LEDs). The analysis was carried out by means of combined electrical and optical measurements. The results of this study indicate that: (i) the main mechanism responsible for reverse-bias current conduction is tunneling, possibly involving structural defects; (ii) the LEDs can emit light when submitted to reverse-bias; (iii) the intensity of reverse-bias luminescence is directly correlated to the reverse current level; (iv) reverse-bias emission is localized around specific spots, that represent preferential paths for leakage current conduction; (v) reverse-bias luminescence is due to carrier recombination taking place in the quantum-well region.