Imaging Localized Energy States in Silicon-doped InGaN Nanowires Using 4D Electron Microscopy

Riya Bose, Aniruddha Adhikari, Victor M Burlakov, Guangyu Liu, Mohammed Haque, Davide Priante, Mohamed N. Hedhili, Nimer Wehbe, Chao Zhao, Haoze Yang, Tien Khee Ng, Alain Goriely, Osman Bakr, Tao Wu, Boon S. Ooi, Omar F. Mohammed

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Introducing dopants into InGaN NWs is known to significantly improve their device performances through a variety of mechanisms. However, to further optimize device operation under the influence of large specific surfaces, a thorough knowledge of ultrafast dynamical processes at the surface and interface of these NWs is imperative. Here, we describe the development of four-dimensional scanning ultrafast electron microscopy (4D S-UEM) as an extremely surface-sensitive method to directly visualize in space and time the enormous impact of silicon doping on the surface-carrier dynamics of InGaN NWs. Two time regime dynamics are identified for the first time in a 4D S-UEM experiment: an early time behavior (within 200 picoseconds) associated with the deferred evolution of secondary electrons due to the presence of localized trap states that decrease the electron escape rate and a longer timescale behavior (several ns) marked by accelerated charge carrier recombination. The results are further corroborated by conductivity studies carried out in dark and under illumination.
Original languageEnglish (US)
Pages (from-to)476-481
Number of pages6
JournalACS Energy Letters
Volume3
Issue number2
DOIs
StatePublished - Jan 30 2018

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