Terahertz spectroscopy of an electron-hole bilayer system in AlN/GaN/AlN quantum wells
Abstract
We report studies on the nanoscale transport dynamics of carriers in strained AlN/GaN/AlN quantum wells: an electron-hole bilayer charge system with a large difference in transport properties between charge layers. From electronic band diagram analysis, the presence of spatially separated two-dimensional electron and hole charge layers is predicted at opposite interfaces. Since these charge layers exhibit distinct spectral signatures at terahertz frequencies, a combination of terahertz and far-infrared spectroscopy enables us to extract (a) individual contributions to the total conductivity and (b) effective scattering rates for charge-carriers in each layer. Furthermore, by comparing direct-current and THz-extracted conductivity levels, we are able to determine the extent to which structural defects affect charge transport. Our results evidence that (i) a non-unity Hall-factor and (ii) the considerable contribution of holes to the overall conductivity lead to a lower apparent mobility in Hall-effect measurements. Overall, our work demonstrates that terahertz spectroscopy is a suitable technique for studying bilayer charge systems with large differences in transport properties between layers such as quantum wells in III-nitride semiconductors.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 14, 2017
- Source ID
- 10.1063/1.4996925
Entities
People
- Ashish Chanana
- B. Sensale-rodriguez
- D. Jena
- H. G. Xing
- Hugo O. Condori Quispe
- Huili Grace Xing
- K. Lee
- R. Chaudhuri
- S. M. Islam
- Samuel J Bader
Organizations
- Air Force Office of Scientific Research
- Cornell University
- Division of Electrical, Communications & Cyber Systems
- Division of Materials Research
- Office of Naval Research
- University of Utah