Leakage Current Characteristics of Nitride-Based InGaN Light-Emitting Diode

Leakage current characteristics have been investigated for nitride-based InGaN light-emitting diodes (LEDs) with different levels of Si-doping conditions applied to the n-type InGaN/GaN layer. The tested LED samples had an emission wavelength of 445 nm. Based on the analysis of temperature-dependent characteristics measurements, the reverse leakage current, I_R, was predominantly influenced by the lowering of Poole-Frenkel (PF) barrier for low electric field (<;2.5 × 10⁶ V/cm) and, for high electric field region (>;8 × 10⁷ V/cm), phonon-assisted tunneling (PAT) dominates the I_R mechanism. The I_R is influenced by the Si-doping density of InGaN/GaN layer that may be present near the end of depletion regions of tested samples.

I. Introduction

Optical degradation in an LED is often accompanied by an increased reverse leakage current across internal junction; and, therefore, it is of great interest to understand the underlying mechanism behind such process to improve modern LED technology [1]–[3]. In this letter, we investigate for the possible dominant effect of doping concentration on in an LED. For the investigation, InGaN-based LEDs with different levels of Si doping concentrations applied to the n-type layer, which is the layer just beneath the InGaN active region illustrated in Fig. 1(a), have been considered. To analyze the results, the (current–voltage–temperature) characteristic has been considered for each of tested samples. We believe that better understanding of the relationship between the doping concentration and the characteristics may enable us to improve the quality of modern LEDs.