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

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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


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, 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 regimes of surface dynamics are identified for the first time in a 4D S-UEM experiment: an early time behavior (within 200 ps) 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 time scale behavior (several ns) marked by accelerated charge carrier recombination. The results are further corroborated by conductivity studies carried out in the dark and under illumination.

Original languageEnglish (US)
Pages (from-to)476-481
Number of pages6
JournalACS Energy Letters
Issue number2
StatePublished - Feb 9 2018

Bibliographical note

Funding Information:
The work reported here was supported by King Abdullah University of Science and Technology (KAUST).

Publisher Copyright:
© 2018 American Chemical Society.

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Energy Engineering and Power Technology
  • Materials Chemistry
  • Fuel Technology
  • Renewable Energy, Sustainability and the Environment


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