Improved blue response and efficiency of A-Si:H solar cells deposited from disilane using a dual-chamber plasma system
Thin film amorphous silicon solar cells with glass/SnO/sub 2//p/i/n/Al structures and 6 to 7% AM1 conversion efficiencies were fabricated at rapid deposition rates in a newly constructed dual-chamber glow discharge deposition system. The 500 nm thick intrinsic layer was deposited at the rate of 1.7 nm/s using disilane (Si/sub 2/H/sub 6/)-helium mixtures. This deposition rate is an order of magnitude greater than conventional high efficiency amorphous silicon solar cell depositions. Residual boron doping effects at the p/i interface can severely degrade cell performance particularly when the intrinsic layer is deposited in one chamber of the dual-chamber system and the intrinsic layer is deposited in the other chamber that is free of boron contaminants. Parameters such as electrode spacing, Si/sub 2/H/sub 6/ partial pressure and flow rate were optimized to produce uniform deposition over large areas. At the substrate temperature T/sub s/ selected for solar cell intrinsic layer deposition, the spin density was measured to be a minimum at 5 x 10/sup 15//cm/sup 3/. For a given T/sub s/, an intrinsic layer deposited from Si/sub 2/H/sub 6/ absorbs fewer photons and can generate less current under solar simulation than a similar film produced from monosilane. Identical solar cells were deposited in either the single-chamber mode or the dual-chamber mode for comparison. Single-chamber mode cells perform poorly over the visible wavelengths and hence produce low short circuit currents. The dual-chamber mode cells show a significant improvement in blue response and a factor of two increase in short circuit current over the single-chamber mode cells. Under short circuit conditions, 15 mA/cm/sup 2/ was generated from rapidly deposited (1.7 nm/s) cells from disilane and 18 mA/cm/sup 2/ from low deposition rate (0.18 nm/s) monosilane cells. These values are comparable to or better than those reported for similar cells by other groups.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 5750109
- Report Number(s):
- BNL-36577; CONF-851043-1; ON: DE85013289
- Resource Relation:
- Conference: 18. IEEE photovoltaic specialists conference, Las Vegas, NV, USA, 21 Oct 1985
- Country of Publication:
- United States
- Language:
- English
Similar Records
Preparation and properties of high-deposition-rate a-Si:H films and solar cells using disilane: Annual subcontract report, 1 May 1987--30 April 1988
Deposition of amorphous silicon solar cells at high rates by glow discharge of disilane. Final subcontract report, January 1985-July 1986
Related Subjects
SILICON SOLAR CELLS
EFFICIENCY
SPECTRAL RESPONSE
AMORPHOUS STATE
CHEMICAL VAPOR DEPOSITION
CURRENT DENSITY
HYDROGEN
QUANTUM EFFICIENCY
CHEMICAL COATING
DEPOSITION
DIRECT ENERGY CONVERTERS
ELEMENTS
EQUIPMENT
NONMETALS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SOLAR CELLS
SOLAR EQUIPMENT
SURFACE COATING
140501* - Solar Energy Conversion- Photovoltaic Conversion