Progress in Silicon Heterojunction Devices by Hot-Wire CVD: Preprint
We report on fabrication of silicon heterojunction (SHJ) solar cells based on Al-backed p-type silicon wafers, with hot-wire chemical vapor deposition (HWCVD) hydrogenated amorphous silicon (a-Si:H) emitter layers. The two-layer emitters are comprised of an extremely thin ({approx}5-nm) intrinsic a-Si:H (a-Si:H(i)) layer topped with a slightly thicker phosphorus-doped a Si:H layer (a-Si:H(n)). Open-circuit voltages (V{sub oc}) above 620 mV are routinely achieved with a maximum of over 640 mV, indicating effective passivation of the crystalline silicon (c-Si) surface by the thin a Si:H(i/n) stack. We used real-time spectroscopic ellipsometry (RTSE) as an in-situ diagnostic tool to monitor film thickness and roughness in real-time and to observe silicon crystallinity by further ex-situ data analysis. The deposited films were also examined by high-resolution transmission electron microscopy (HRTEM). Immediate a-Si:H deposition and a flat interface to the c-Si is the key factor in obtaining high V{sub oc}. On commercial p-type B-doped Czochralski silicon (CZ-Si) wafers with a polished surface and 2.1 {Omega}{center_dot}cm resistivity, the best efficiency obtained is 14.8%. Efficiency above 15.7% is achieved on a 1.3 {Omega}{center_dot}cm, p-type B-doped float-zone silicon (FZ-Si) wafer with a chemically polished front surface and a screen-printed Al-BSF.
- Research Organization:
- National Renewable Energy Lab., Golden, CO (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC36-99-GO10337
- OSTI ID:
- 15009888
- Report Number(s):
- NREL/CP-520-36668; TRN: US200430%%1571
- Resource Relation:
- Conference: Prepared for the 14th Workshop on Crystalline Silicon Solar Cells and Materials, Winter Park, CO (US), 08/08/2004--08/11/2004; Other Information: PBD: 1 Aug 2004
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
14 SOLAR ENERGY
CHEMICAL VAPOR DEPOSITION
DATA ANALYSIS
DEPOSITION
EFFICIENCY
ELLIPSOMETRY
FABRICATION
HETEROJUNCTIONS
MONITORS
PASSIVATION
ROUGHNESS
SILICON
SILICON SOLAR CELLS
SOLAR CELLS
THICKNESS
TRANSMISSION ELECTRON MICROSCOPY
PV
PHOTOVOLTAICS
CRYSTALLINE SILICON
MATERIALS AND PROCESSES
MODULE
IMPURITIES
DEVICE PROCESS
CRYSTAL GROWTH
DEFECT
MICROELECTRONICS
SOLAR ENERGY - PHOTOVOLTAICS