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Enhanced Optoelectronic Performance of a Passivated Nanowire‐Based Device: Key Information from Real‐Space Imaging Using 4D Electron Microscopy
Author(s) -
Khan Jafar I.,
Adhikari Aniruddha,
Sun Jingya,
Priante Davide,
Bose Riya,
Shaheen Basamat S.,
Ng Tien Khee,
Zhao Chao,
Bakr Osman M.,
Ooi Boon S.,
Mohammed Omar F.
Publication year - 2016
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201503651
Subject(s) - ultrashort pulse , materials science , optoelectronics , passivation , nanowire , nanotechnology , electron , bottleneck , laser , optics , computer science , physics , layer (electronics) , quantum mechanics , embedded system
Managing trap states and understanding their role in ultrafast charge‐carrier dynamics, particularly at surface and interfaces, remains a major bottleneck preventing further advancements and commercial exploitation of nanowire (NW)‐based devices. A key challenge is to selectively map such ultrafast dynamical processes on the surfaces of NWs, a capability so far out of reach of time‐resolved laser techniques. Selective mapping of surface dynamics in real space and time can only be achieved by applying four‐dimensional scanning ultrafast electron microscopy (4D S‐UEM). Charge carrier dynamics are spatially and temporally visualized on the surface of InGaN NW arrays before and after surface passivation with octadecylthiol (ODT). The time‐resolved secondary electron images clearly demonstrate that carrier recombination on the NW surface is significantly slowed down after ODT treatment. This observation is fully supported by enhancement of the performance of the light emitting device. Direct observation of surface dynamics provides a profound understanding of the photophysical mechanisms on materials' surfaces and enables the formulation of effective surface trap state management strategies for the next generation of high‐performance NW‐based optoelectronic devices.