Strain Loading Mode Dependent Bandgap Deformation Potential in ZnO Micro/Nanowires. ACS Nano (2015)

ACS Nano
Xuewen Fu, Zhi-Min Liao, Ren Liu, Fang Lin, Jun Xu, Rui Zhu, Wei Zhong, Yingkai Liu, Wanlin Guo,and Dapeng Yu
DOI 10.1021/acsnano.5b04617
State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, P. R. China, ‡Collaborative Innovation Center of Quantum
Matter,Beijing100871,P.R.China, KeyLaboratoryofYunnanHigherEducationInstitutesforOptoelectricInformation&Technology,Kunming650500,P.R.China, and State Key Laboratory of Mechanics and Control of Mechanical Structures and Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, P. R. China
Strain Loading Mode Dependent Bandgap Deformation Potential in ZnO Micro/Nanowires.

ABSTRACT
The electronic-mechanical coupling in semiconductor nanostructures under different strain loading modes can modulate their photoelectric properties in different manners. Here, we report the systematic investigation on the strain mode dependent bandgap deformation potential of ZnO micro/nanowires under both uniaxial tensile and bending strains at room temperature. Uniaxial stretching-photoluminescence results show that the deformation potential of the smaller ZnO nanowire (with diameter d = 260 nm) is 30.6 meV/%, and is close to the bulk value, whereas it deviates the bulk value and becomes to be 10.6 meV/% when the wire diameter is increased to d = 2 μm. This unconventional size dependence stems from surface effect induced inhomogeneous strain in the surface layer and the core of the ZnO micro/nanowires under uniaxial tension. Forbendingloadmode, the in situhigh-resolution transmission electron microscope analysis reveals that the local strain distributes linearly in the bending crosssection.Further cathodoluminescence measurements on a bending ZnO microwire(d=1.8 μm)demonstrate that the deformation potentialis 27meV/%,whose absolute value is much larger than that of the ZnO microwire under uniaxial tension. Further analysis reveals that the distinct deformation potentials originate from the different deforming modes in ZnO micro/nanowires under bending or uniaxial tensile strains. Our results should facilitate the design of flexible optoelectronic nanodevices.

http://pubs.acs.org/doi/abs/10.1021/acsnano.5b04617

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