Observation of piezotronic and piezo-phototronic effects in n-InGaN nanowires/Ti grown by molecular beam epitaxy

Malleswararao Tangi*, Jung Wook Min, Davide Priante, Ram Chandra Subedi, Dalaver H. Anjum, Aditya Prabaswara, Nasir Alfaraj, Jian Wei Liang, Mohammad Khaled Shakfa, Tien Khee Ng, Boon S. Ooi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Group-III nitride nano-dimensional materials with noncentrosymmetric crystal structure offer an exciting area of piezotronics for energy conversion applications. We experimentally report the piezotronic and piezo-phototronic effects of n-InGaN nanowires (NWs) having an emission wavelength in the visible region (≈510 nm). The n-type InGaN NWs, exhibiting high structural and optical quality, were grown by plasma-assisted molecular beam epitaxy (PAMBE) on Ti/TaN/Si substrates to facilitate the direct bottom electrical contact to the NWs. Further, we use Pt/Ir conductive atomic force microscopy (c-AFM) tip as a top electrical contact to the NW. Applying compressive strain on the NWs using a c-AFM tip, the Schottky barrier height (SBH) formed at the metal-semiconductor NW interface was tuned by means of strain induced piezo-potential. Thus, we study the two-way coupling of mechanical and electrical energy results in piezotronics of n-InGaN NWs. Such measurements were further carried out under optical excitation with 405 nm laser to understand its effect on change in SBH. Thereby, we demonstrate the three-way coupling of the piezo-phototronics of n-InGaN NWs by exploiting their excellent visible optoelectronic properties. The photogenerated carriers reduce the SBH while they play a lesser role at higher tip deflection force on NWs. This revealed that at the higher strain on NW, the piezo fields screen the photoexcited carriers hence resulting in a negligible change in I-V characteristics for ≥ 6 nN tip force with and without illumination. Thus, the investigation of nanoscale piezotronic and piezo-phototronic effects of n-InGaN NWs provides an opportunity to enable piezoelectric functional devices to be used as strain-tunable, self-powered electronics and optoelectronics applications.

Original languageEnglish (US)
Pages (from-to)264-271
Number of pages8
JournalNano Energy
Volume54
DOIs
StatePublished - Dec 2018

Keywords

  • Piezo-phototronics
  • Piezotronics
  • Wurtzite
  • n-InGaN nanowires

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • General Materials Science
  • Renewable Energy, Sustainability and the Environment

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