Bandgap and Carrier Transport Engineering of Quantum Confined Mixed Phase Nanocrystalline/Amorphous Silicon
Mixed phase nanocrystalline/amorphous-silicon (nc/a-Si:H) thin films with band-gap higher than bulk silicon are prepared by depositing silicon nanoparticles (SiNPs), prepared in a separate deposition zone, and hydrogenated amorphous silicon (a-Si:H), simultaneously. Since the two deposition phases are well decoupled, optimized parameters for each component can apply to the growth process. Photoluminescence spectroscopy (PL) shows that the embedded SiNPs are small enough to exhibit quantum confinement effects. The low temperature PL measurements on the mixed phase reveal a dominant emission feature, which is associated with SiNPs surrounded by a-Si:H. In addition, we compare time dependent low temperature PL measurements for both a-Si:H and mixed phase material under intensive laser exposure for various times up to two hours. The PL intensity of a-Si:H with embedded SiNPs degrades much less than that of pure a-Si:H. We propose this improvement of photostability occurs because carriers generated in the a-Si:H matrix quickly transfer into SiNPs and recombine there instead of recombining in a-Si:H and creating defect states (Staebler-Wronski Effect).
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- Solar Energy Research Institute for India and the U.S. (SERIIUS); USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office; USDOE International Affairs
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1343667
- Report Number(s):
- NREL/CP-5J00-67939
- Resource Relation:
- Conference: Presented at the 2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC), 5-10 June 2016, Portland, Oregon
- Country of Publication:
- United States
- Language:
- English
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