The coupling influence of UV illumination and strain on the surface potential distribution of a single ZnO micro/nano wire
ZnO, ultraviolet illumination, strain, surface potential
Interface/surface properties play an important role in the development of mostelectronic devices. In particular, nanowires possess large surface areas that createnew challenges for their optoelectronic applications. Here, we demonstrated thatthe piezoelectric field and UV laser illumination modulate the surface potentialdistribution of a bent ZnO wire by the Kelvin probe force microscopy technology.Experiments showed that the surface potential distribution was changed bystrain. The difference of surface potential between the outer/inner sides ofthe ZnO wire increased with increasing strain. Under UV laser illumination, thedifference of surface potential between the outer/inner sides of the ZnO wireincreased with increasing strain and illumination time. The origin of the observedphenomenon was discussed in terms of the energy band diagram of the bentwire and adsorption/desorption theory. It is suggested that the change of surfacepotential can be attributed to the uneven distribution of the carrier density acrossthe wire deduced by the piezoelectric effect and surface adsorption/desorptionof oxygen ions. This study provides an important insight into the surface andpiezoelectric effects on the surface potential and can help optimize the performanceof electronic and optoelectronic devices.
Tsinghua University Press
Zhao Wu,Junjie Qi,Feng Li,Xiaoyang Zhu,Zengze Wang,Guangjie Zhang,Yue Zhang, The coupling influence of UV illumination and strain on the surface potential distribution of a single ZnO micro/nano wire. NanoRes.2016, 9(9): 2572–2580