title: Exciton drift in semiconductors under uniform strain gradients: application to bent ZnO microwires.
abstract: Optimizing the electronic structures and carrier dynamics in semiconductors at atomic scale is an essential issue for innovative device applications. Besides the traditional chemical doping and the use of homo/heterostructures, elastic strain has been proposed as a promising possibility. Here, we report on the direct observation of the dynamics of exciton transport in a ZnO microwire under pure elastic bending deformation, by using cathodoluminescence with high temporal, spatial, and energy resolutions. We demonstrate that excitons can be effectively drifted by the strain gradient in inhomogeneous strain fields. Our observations are well reproduced by a drift-diffusion model taking into account the strain gradient and allow us to deduce an exciton mobility of 1400 ± 100 cm(2)/(eV s) in the ZnO wire. These results propose a way to tune the exciton dynamics in semiconductors and imply the possible role of strain gradient in optoelectronic and sensing nano/microdevices.
authors.affiliation: State Key Laboratory for Mesoscopic Physics, and Electron Microscopy Laboratory, Department of Physics, Peking University , 209 Chengfu Road, Beijing 100871, China.
authors.forename: Xuewen
authors.initials: X
authors.lastname: Fu
authors.forename: Gwenole
authors.initials: G
authors.lastname: Jacopin
authors.forename: Mehran
authors.initials: M
authors.lastname: Shahmohammadi
authors.forename: Ren
authors.initials: R
authors.lastname: Liu
authors.forename: Malik
authors.initials: M
authors.lastname: Benameur
authors.forename: Jean-Daniel
authors.initials: JD
authors.lastname: Ganière
authors.forename: Ji
authors.initials: J
authors.lastname: Feng
authors.forename: Wanlin
authors.initials: W
authors.lastname: Guo
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Liao
authors.forename: Benoit
authors.initials: B
authors.lastname: Deveaud
authors.forename: Dapeng
authors.initials: D
authors.lastname: Yu