1. Energy Storage and Conversion Devices Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu, India
2. Department of Energy Science Engineering, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, South Korea
3. Semiconductor Electronics Department, Lviv Polytechnic National University, 12 Bandera Street, Lviv 79013, Ukraine