1. College of Chemistry and Chemical Engineering Central South University Changsha 410083 China
2. School of Physics and Optoelectronics Xiangtan University Xiangtan 411105 China
3. Department of Semiconductors Materials and Energy Research Center P.O. Box 14155/4777 Tehran 3177983634 Iran
4. School of Material Science and Engineering Zhengzhou University Zhengzhou 450001 China