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

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


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 languageBritish English
Pages (from-to)264-271
Number of pages8
JournalNano Energy
StatePublished - Dec 2018


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


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