Details

Autor(en) / Beteiligte

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

Titel

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

Ist Teil von

• Nano energy, 2018-12, Vol.54, p.264-271

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2018

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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. The two-way coupling of mechanical and electrical energy is examined by applying external compressive strain on the n-InGaN nanowires (NWs), using a c-AFM Pt/Ir conductive tip, which induced a piezoelectric potential in the NW. Furthermore, the piezo-phototronic effect associated with the three-way coupling of n-InGaN NWs is demonstrated by exploiting their excellent visible optoelectronic properties. Under optical excitation, the photogenerated carriers reduce the strain induced SBH. At higher compressive strain, no change in the I-V characteristics was observed which reveals the dominant role of strain induced piezo fields. [Display omitted] •We report the first systematic study on the piezotronic and piezo-phototronic effects in n-type InGaN nanowires (NWs) with the well-revealed mechanism.•The two-way coupling of mechanical and electrical energy is verified by applying external compressive strain on the NWs using a c-AFM Pt/Ir conductive tip.•The piezo-phototronics effect using the three-way coupling of n-InGaN NWs is demonstrated by exploiting their excellent visible optoelectronic properties. Under optical excitation, the photogenerated carriers reduce the strain induced SBH.•The change in SBH with and without illumination exhibited a linear relationship with the external compressive strain.•At higher compressive strain, the piezo fields have a dominant role over the optical excitation induced fields.