1. Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, USA
2. Department of Physics and Astronomy, Texas Tech University, Lubbock, Texas 79409, USA
3. Nano Tech Center, Texas Tech University, Lubbock, Texas 79409, USA
4. Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, USA
5. Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409, USA