Open AccessEffect of electron blocking layer on the efficiency of AlGaN mid-ultraviolet light emitting diodes
Author(s) -
Ayush Pandey,
Walter Shin,
X Liu,
Zetian Mi
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.00a738
Subject(s) - materials science , optoelectronics , superlattice , light emitting diode , quantum efficiency , blocking (statistics) , diode , wafer , layer (electronics) , ultraviolet , scanning electron microscope , electron , quantum well , optics , nanotechnology , laser , physics , composite material , statistics , mathematics , quantum mechanics
The performance of AlGaN-based mid and deep ultraviolet light emitting diodes (LEDs) is severely limited by electron overflow and by the poor hole injection into the device active region. We have studied the effect of various electron blocking layers on the performance of AlGaN LEDs operating at ~280 nm. It is observed that, compared to conventional p-type electron blocking layer, the incorporation of an n-type AlN/AlGaN superlattice electron blocking layer before the active region can significantly improve the device performance by reducing electron overflow without compromising hole injection. Direct on-wafer measurement showed an external quantum efficiency ~4.4% and wall-plug efficiency ~2.8% by optimizing the design of n-type AlN/AlGaN superlattice electron blocking layer, which is nearly a factor of five to ten times better than identical devices but with the incorporation of a conventional p-type electron blocking layer.