Performance enhancement with thin p-AlInN electron-blocking layer in ultraviolet light-emitting diodes

Abstract

.III-nitride ultraviolet light-emitting diodes (UV LEDs) face low carrier confinement and poor p-doping. In this study, we propose a thin AlInN electron-blocking layer (EBL) in UV LEDs instead of conventional AlGaN EBL. Numerical results demonstrate that UV LED with thin AlInN enhances the optoelectronic performance. The results also reveal that AlGaN EBL is more sensitive to p-doping as compared to AlInN EBL. Thin AlInN layer facilitates hole transportation through intra-band tunneling. Moreover, AlInN has a high conduction band offset that suppresses the electron leakage effectively. Hence, the carrier radiative recombination rate considerably enhances with thin AlInN EBL. The efficiency droop in the proposed LED is also alleviated.

Metal-modulated epitaxy of Mg-doped Al0.80In0.20N-based layer for application as the electron blocking layer in deep ultraviolet light-emitting diodes

“…Experimental results noted the importance of thickness in the AlInN growth and doping processes, moreover, the MME approach improves the metal incorporation without clustering and benefits the incorporation of In atoms due to the lower growth temperature employed. Theoretical and numerical research has shown that the AlInN-based layer is suitable as EBL for DUV-LED development due to the increase in radiative recombination rates, electron leakage mitigation, and the resulting hole injection into the active region, using a few nanometers layer [14,17] . In this work, the thickness of the ptype Al x In 1−x N EBL was set to 13 nm to evaluate the effect of indium content in the EBL.…”

“…10(a). While the confinement increases and the hole injection is improved using p-AlInN-based EBL [14,15] , there exists a spillover of holes into the quantum barriers, increasing the probability of recombination, even radiative, in the barriers [53] . However, the increased power spectral density was observed as illustrated in Fig.…”

“…In this case, these characteristics have resulted useful substitute for the traditional AlGaN-based quantum barriers. It has been observed that p-type doping of AlInN layers provides lower internal quantum efficiency drop, lower electric field, and higher radiative recombination increasing the light output power [14] . Moreover, the carrier injection is improved due to the higher conduction band offset compared to AlGaN [10] .…”

“…Despite the AlInN-based electron blocking layers (EBL) has revealed an alternative to increasing the DUV-LED efficiency by increasing the confinement and enhancing the hole injection into the active region [14,17] , the high segregation to the surface [12] and interdiffusion [18] are current problems that hinder the proper incorporation of In-atoms, making it essential to overcome these disadvantages by avoiding high growth temperatures. Indium nitride (InN) requires lower growth temperatures than aluminum and gallium nitrides due to the higher atomic mobility of In atoms, the ther-modynamical instability, and its trend to segregate to the surface [19] .…”