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Local carrier recombination and associated dynamics in m-plane InGaN/GaN quantum wells probed by picosecond cathodoluminescence

Accepted version
Peer-reviewed

Type

Article

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Authors

Gachet, D 
Tang, F 
Fu, WY 
Oehler, F 

Abstract

We report on spatially resolved and time-resolved cathodoluminescence (CL) studies of the recombination mechanisms of InGaN/GaN quantum wells (QWs) grown by metal-organic vapour phase epitaxy on bulk m-plane Ammono GaN substrates. As a result of the 2° miscut of the GaN substrate, the sample surface exhibits step bunches, where semi-polar QWs with a higher indium concentration than the planar m-plane QWs form during the QW growth. Spatially resolved time-integrated CL maps under both continuous and pulsed excitation show a broad emission band originating from the m-plane QWs and a distinct low energy emission originating from the semi-polar QWs at the step bunches. High resolution time-resolved CL maps reveal that when the m-QWs are excited well away from the step bunches the emission from the m-plane QWs decays with a time constant of 350 ps, whereas the emission originating semi-polar QWs decays with a longer time constant of 489 ps. The time constant of the decay from the semi-polar QWs is longer due to the separation of the carrier wavefunctions caused by the electric field across the semi-polar QWs.

Description

Keywords

51 Physical Sciences

Journal Title

Applied Physics Letters

Conference Name

Journal ISSN

0003-6951
1077-3118

Volume Title

109

Publisher

AIP Publishing
Sponsorship
Engineering and Physical Sciences Research Council (EP/H019324/1)
Engineering and Physical Sciences Research Council (EP/I012591/1)
Engineering and Physical Sciences Research Council (EP/J003603/1)
Engineering and Physical Sciences Research Council (EP/M010589/1)
Engineering and Physical Sciences Research Council (EP/M011682/1)
Engineering and Physical Sciences Research Council (TS/G001383/1)
European Research Council (279361)
This work has been funded by the EPSRC (Grant Nos. EP/J003603/1, EP/J001627/1, and EP/M011682/1) and in part by the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC Grants Agreement No. 279361 (MACONS).
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