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Study of Intraband absorption in InGaN disk of a GaN/AlGaN core-shell nanowire
- Author(s)
- AKTER, AFROJA
- Advisor
- Junseok Heo
- Department
- 일반대학원 전자공학과
- Publisher
- The Graduate School, Ajou University
- Publication Year
- 2016-08
- Language
- eng
- Alternative Abstract
- This thesis investigates the intraband absorption in a InGaN disk of GaN/AlGaN core-shell nanowire. First, how the cladding of AlGaN plays significant role to enhance the intraband absorption intensity and energy after modifing the internal electric field of the quantum disk of In0.3Ga0.7N in a GaN nanowire comparing with palin GaN nanowire investigated. Presence of cladding material in the nanowire makes more centralized electron probability density in the conduction band. Hence cladding overcome the band bending effect and enhances the overlapping of subband electronic states. As a result in a cladding nanowire the intraband absorption intensity dominate over plain nanowire. After that how the indium composition rate in the disk of cladding (Al0.4Ga0.6N layer) GaN nanowire changes the intraband absorption is investigated. With increasing In composition in the disk linearly decrease the intraband absorption intensity, with blue shift of absorption energy. Increasing In composition in the disk increase internal electric field with decrease the magnitude of the probability density of each state due to stack effect hence decrease the subband electronic states overlapping. Thus the absorption intensity become decreases. At the same time high piezoelectric field enhance the charge accumulation in the high indium disk, which increase the absorption intensity. Theoretical investigation shows the mid wavelength IR absorption for in-plane polarized light at 17.8 µm, 16.33 µm and ~15 µm for 20%, 25% and for 30% In in the disk respectively. At room temperature the FTIR measurement of the nanowire sample shows the intraband absorption from 14 to 17.96 µm with maximum peak at ~15 µm wavelength, which support the theoretical investigation. Finally here it can suggest that this nanowire can use in mid- IR optoelectronic applications.
- Fulltext
- Appears in Collections:
- Graduate School of Ajou University > Department of Electronic Engineering > 3. Theses(Master)
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