Study of GaN/InGaN Light-Emitting Diodes with Specific Zirconium Oxide (ZrO2) Layers

Abstract

An interesting device design including a zirconium oxide (ZrO2) current blocking layer (CBL) and a ZrO2 surface passivation layer (SPL) is employed to manufacture a GaN/InGaN light-emitting diode (LED). Based on the inherently good performance of ZrO2, the current spreading effect and the undesired surface leakage are efficiently enhanced and suppressed, respectively. Energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) are used to study the relevant properties. It is found that by series calibration, 50 nm is the proper thickness of the ZrO2 CBL and SPL. The peak emission wavelength of the proposed LEDs is around 452 nm. Experimentally, at the operating condition of 110 A cm−2, the proposed Device L3 with a 50 nm-thick ZrO2 CBL and a 50 nm-thick ZrO2 SPL demonstrates improvements of 66.1% in light output power (LOP) and 64.5% in wall plug efficiency (WPE) as compared to a traditional Device L1 without the specific design. Furthermore, the proposed Device L3 presents a notable enhancement in the light emission mapping image in comparison to the traditional LED. So, the proposed device design which incorporates a proper ZrO2 CBL and ZrO2 SPL, is beneficial for manufacturing GaN/InGaN LEDs.