Bandgap and exciton binding energies of hexagonal boron nitride probed by photocurrent excitation spectroscopy
Abstract
Photocurrent excitation spectroscopy has been employed to probe the band structure and basic parameters of hexagonal boron nitride (h-BN) epilayers synthesized by metal-organic chemical vapor deposition. Bias dependent photocurrent excitation spectra clearly resolved the band-to-band, free exciton, and impurity bound exciton transitions. The energy bandgap (Eg), binding energy of free exciton (Ex), and binding energy of impurity bound exciton (Ebx) in h-BN have been directly obtained from the photocurrent spectral peak positions and comparison with the related photoluminescence emission peaks. The direct observation of the band-to-band transition suggests that h-BN is a semiconductor with a direct energy bandgap of Eg = 6.42 eV at room temperature. These results provide a more coherent picture regarding the fundamental parameters of this important emerging ultra-wide bandgap semiconductor.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 19, 2016
- Source ID
- 10.1063/1.4963128
Entities
People
- Hongxing Jiang
- Jing Li
- Jingyu Lin
- T. C. Doan
Organizations
- Army Research Office
- National Science Foundation
- Texas Tech University