Improving carrier transport in AlGaN deep-ultraviolet light-emitting diodes using a strip-in-a-barrier structure

Abstract

This paper reports the illustration of electron blocking layer (EBL)-free AlGaN light-emitting diodes (LEDs) operating in the deep-ultraviolet (DUV) wavelength at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>270</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">n</mml:mi> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:math> . In this work, we demonstrated that the integration of an optimized thin undoped AlGaN strip layer in the middle of the last quantum barrier (LQB) could generate enough conduction band barrier height for the effectively reduced electron overflow into the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>p</mml:mi> <mml:mtext>-</mml:mtext> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">G</mml:mi> <mml:mi mathvariant="normal">a</mml:mi> <mml:mi mathvariant="normal">N</mml:mi> </mml:mrow> </mml:math> region. Moreover, the hole injection into the multi-quantum-well active region is significantly increased due to a large hole accumulation at the interface of the AlGaN strip and the LQB. As a result, the internal quantum efficiency and output power of the proposed LED structure has been enhanced tremendously compared to that of the conventional <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>p</mml:mi> <mml:mtext>-</mml:mtext> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">t</mml:mi> <mml:mi mathvariant="normal">y</mml:mi> <mml:mi mathvariant="normal">p</mml:mi> <mml:mi mathvariant="normal">e</mml:mi> </mml:mrow> </mml:math> EBL-based LED structure.

Topics & Concepts