Recent progress in amorphous silicon alloy leading to 13% stable cell efficiency

Significant progress has been made in amorphous silicon (a-Si) alloy solar cells using a spectral-splitting, triple-junction structure in which the bandgap of each component cell is designed to absorb a different portion of the solar spectrum. Key factors leading to the stable 13% active-area cell efficiency include: (i) using a high hydrogen dilution technique during the growth of the intrinsic layers, (ii) employing a bandgap profiling design for the a-SiGe alloy cells, (iii) incorporating appropriate current mismatch for component cells, (iv) developing microcrystalline doped layers for the tunnel junctions and the window layer, (v) enhancing the light trapping effect of the textured back reflector, and (vi) improving the performance of the top conducting oxide layer. These factors along with other developments relevant to the achievement of high efficiency cells are discussed.

[1]  Stanford R. Ovshinsky,et al.  Band‐gap profiling for improving the efficiency of amorphous silicon alloy solar cells , 1989 .

[2]  Isaac Balberg,et al.  Deposition of device quality, low H content amorphous silicon , 1991 .

[3]  Stanford R. Ovshinsky,et al.  Effect of hydrogen dilution on the structure of amorphous silicon alloys , 1997 .

[4]  S. Guha,et al.  Triple-junction amorphous silicon alloy solar cell with 14.6% initial and 13.0% stable conversion efficiencies , 1997 .

[5]  A. Matsuda,et al.  Glow-discharge amorphous silicon: Growth process and structure , 1987 .

[6]  S. Guha,et al.  Improved stability against light exposure in amorphous deuterated silicon alloy solar cell , 1997 .

[7]  A. Gallagher,et al.  Surface reaction probability of film‐producing radicals in silane glow discharges , 1990 .

[8]  Makoto Tanaka,et al.  Effects of high hydrogen dilution at low temperature on the film properties of hydrogenated amorphous silicon germanium , 1997 .

[9]  A Study of a-Si:H/a-SiGe:H Tandem Solar Cells and Modules , 1994 .

[10]  M. Vaněček,et al.  A reduction in the Staebler‐Wronski effect observed in low H content a‐Si:H films deposited by the hot wire technique , 1991 .

[11]  S. M. Pietruszko,et al.  On light‐induced effect in amorphous hydrogenated silicon , 1981 .

[12]  S. Wagner,et al.  Band edge discontinuities between microcrystalline and amorphous hydrogenated silicon alloys and their effect on solar cell performance , 1995 .

[13]  Subhendu Guha,et al.  Enhancement of open circuit voltage in high efficiency amorphous silicon alloy solar cells , 1986 .

[14]  D. Staebler,et al.  Reversible conductivity changes in discharge‐produced amorphous Si , 1977 .

[15]  D. Carlson,et al.  AMORPHOUS SILICON SOLAR CELL , 1976 .

[16]  Stanford R. Ovshinsky,et al.  Amorphous Silicon Alloy Photovoltaic Technology - from R&D to Production , 1994 .

[17]  N. Hata,et al.  Deposition and extensive light soaking of highly pure hydrogenated amorphous silicon , 1996 .

[18]  S. Guha,et al.  Double‐junction amorphous silicon‐based solar cells with 11% stable efficiency , 1992 .

[19]  Liyou Yang,et al.  The Effect of H 2 Dilution on the Stability of a-Si:H based Solar Cells , 1994 .