1. Department of Electronics Quaid-i-Azam University Islamabad 45320 Pakistan
2. Solid State Electronic Devices Lab Experimental Physics Department National Centre for Physics Quaid-i-Azam University Campus Shahdara Valley Road Islamabad 45320 Pakistan
3. School of Electrical Engineering and Computer Science (EECS) KTH Royal Institute of Technology 16440 Kista Sweden
4. Pakistan Academy of Sciences (member) Islamabad 45320 Pakistan