Carrier Blocking Layer Analysis for High Integral Confinement Factor of AlGaN-based Deep-Ultraviolet Light-Emitting Diode

Abstract

Abstract The deep-ultraviolet light-emitting diode (DUV-LED) has been applied in various fields such as the medical sector, plant lighting, UV curing, sensing, and sterilization. Alas, the issue of low internal quantum efficiency (IQE) due to the defects in the epitaxial layer has become an obstacle in developing and improving the performance of the DUV-LED. In this regard, the electron blocking layer (EBL) and hole blocking layer (HBL) is one of the means to obtain DUV-LED with high IQE. The EBL main purposes are to block the overflow of carriers and improve the carrier confinement in the active region, hence enhance the radiative recombination of the DUV-LED. Employing the blocking layers via controlled-polarization offers significant advantage to the DUV-LED. Two structures of AlGaN-based DUV-LED emitting UVB wavelength spectrum were simulated and investigated, (1) LED A (reference LED) with the absence of EBL and HBL, and (2) LED B with the presence of EBL and HBL. The numerical analysis covers the optoelectronics performance parameters of the chips such as band diagram, carrier concentrations, radiative recombination rates, luminescence spectrum and IQE. A novel approach for quantifying the confinement ability called the integral confinement factor (ICF) is introduced to analyze the carrier for the blocking layers. It is found that with the presence of EBL and HBL in the DUV-LED structure, the luminescence intensity and IQE have been amplified by 16% and 50% compared to the reference LED, respectively.