title: Structural and optical characterization of ZnO/Mg(x)Zn(1-x)O multiple quantum wells based random laser diodes.
abstract: Two kinds of laser diodes (LDs) comprised of ZnO/Mg(x)Zn(1-x)O (ZnO/MZO) multiple quantum wells (MQWs) grown on GaN (MQWs/GaN) and Si (MQWs/Si) substrates, respectively, have been constructed. The LD with MQWs/GaN exhibits ultraviolet random lasing under electrical excitation, while that with MQWs/Si does not. In the MQWs/Si, ZnO/MZO MQWs consist of nanoscaled crystallites, and the MZO layers undergo a phase separation of cubic MgO and hexagonal ZnO. Moreover, the Mg atom predominantly locates in the MZO layers along with a significant aggregation at the ZnO/MZO interfaces; in sharp contrast, the ZnO/MZO MQWs in the MQWs/GaN show a well-crystallized structure with epitaxial relationships among GaN, MZO, and ZnO. Notably, Mg is observed to diffuse into the ZnO well layers. The structure-optical property relationship of these two LDs is further discussed.
authors.affiliation: School of Physics and Technology, Center for Electron Microscopy and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, People's Republic of China.
authors.forename: Qike
authors.initials: Q
authors.lastname: Jiang
authors.forename: He
authors.initials: H
authors.lastname: Zheng
authors.forename: Jianbo
authors.initials: J
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Long
authors.forename: Guojia
authors.initials: G
authors.lastname: Fang