Significant mobility enhancement in extremely thin highly doped ZnO films
Abstract
Highly Ga-doped ZnO (GZO) films of thicknesses d = 5, 25, 50, and 300 nm, grown on 160-nm ZnO buffer layers by molecular beam epitaxy, had 294-K Hall-effect mobilities μH of 64.1, 43.4, 37.0, and 34.2 cm2/V-s, respectively. This extremely unusual ordering of μH vs d is explained by the existence of a very high-mobility Debye tail in the ZnO, arising from the large Fermi-level mismatch between the GZO and the ZnO. Scattering theory in conjunction with Poisson analysis predicts a Debye-tail mobility of 206 cm2/V-s at the interface (z = d), falling to 58 cm2/V-s at z = d + 2 nm. Excellent fits to μH vs d and sheet concentration ns vs d are obtained with no adjustable parameters.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 13, 2015
- Source ID
- 10.1063/1.4917561
Entities
People
- Chen Yang
- D. C. Look
- Eric R. Heller
- Yu-feng Yao
Organizations
- Air Force Office of Scientific Research
- Air Force Research Laboratory
- National Safety Council
- National Science Foundation
- National Science and Technology Council
- National Taiwan University
- Wright State University