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ENHANCED PHOTOVOLTAIC DEVICES VIA THE USE OF LARGE OPTICAL BANDGAP DOPED a-Si:H PRODUCED VIA H-CVD

IP.com Disclosure Number: IPCOM000043276D
Original Publication Date: 1984-Aug-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 1 page(s) / 13K

Publishing Venue

IBM

Related People

Meyerson, BS: AUTHOR [+2]

Abstract

This article discusses how improved performance in a p-i-n or p-n photovoltaic device is obtainable by properly tailoring the optical gap of each device layer to its purpose, and how the use of H-CVD (homogenous chemical vapor deposition) helps achieve this improved performance. Photovoltaic devices produced by the glow-discharge decomposition of silane (SiH4) suffer efficiency losses due to low hole mobilities and/or high recombination rates in the p-type material of p-n and p-i-n structures. The collection efficiency of a p-i-n cell structure may be enhanced by utilizing p-type material with a large optical bandgap relative to that of boron-doped glow discharge a-Si:H (i.e., Eopt>1.7 eV).

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ENHANCED PHOTOVOLTAIC DEVICES VIA THE USE OF LARGE OPTICAL BANDGAP DOPED a-Si:H PRODUCED VIA H-CVD

This article discusses how improved performance in a p-i-n or p-n photovoltaic device is obtainable by properly tailoring the optical gap of each device layer to its purpose, and how the use of H-CVD (homogenous chemical vapor deposition) helps achieve this improved performance. Photovoltaic devices produced by the glow-discharge decomposition of silane (SiH4) suffer efficiency losses due to low hole mobilities and/or high recombination rates in the p-type material of p-n and p-i-n structures. The collection efficiency of a p-i-n cell structure may be enhanced by utilizing p-type material with a large optical bandgap relative to that of boron-doped glow discharge a-Si:H (i.e., Eopt>1.7 eV). This would result in the transmission of a greatly increased photon flux into the underlying i- and n-type layers, which collect them with far greater efficiency. The success of this concept was demonstrated by Tawada et al [*], who incorporated carbon into their p-type layer, which resulted in a 2.l eV optical gap silicon-carbon compound. A claim of 7.14% conversion efficiency was made for a a-Si:C B:H/a-Si:H/ a-Si:H:P cell vs. 5.5% efficiency for the identical structure minus the carbon content in the p-type layer. According to the figures just cited, this amounted to a 30% improvement in overall device performance by the tailoring of the p-type layer's optical gap. As a straightforward improvement on this concept, sever...