title: Enhanced Optoelectronic Performance of a Passivated Nanowire-Based Device: Key Information from Real-Space Imaging Using 4D Electron Microscopy.
abstract: 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.
authors.affiliation: Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Jafar I
authors.initials: JI
authors.lastname: Khan
authors.affiliation: Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Aniruddha
authors.initials: A
authors.lastname: Adhikari
authors.affiliation: Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Jingya
authors.initials: J
authors.lastname: Sun
authors.affiliation: Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Davide
authors.initials: D
authors.lastname: Priante
authors.affiliation: Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Riya
authors.initials: R
authors.lastname: Bose
authors.affiliation: Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Basamat S
authors.initials: BS
authors.lastname: Shaheen
authors.affiliation: Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Tien Khee
authors.initials: TK
authors.lastname: Ng
authors.affiliation: Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Osman M
authors.initials: OM
authors.lastname: Bakr
authors.affiliation: Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Boon S
authors.initials: BS
authors.lastname: Ooi
authors.affiliation: Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Omar F
authors.initials: OF
authors.lastname: Mohammed
keywords: 4D ultrafast microscopy; InGaN nanowires; carrier recombination; charge carrier dynamics; passivation