Optimizing emitter-buffer layer stack thickness for p-type silicon heterojunction solar cells

p-type silicon heterojunction solar cells are investigated in terms of doping concentration of emitter a-Si:H(n) layer and thickness of emitter-intrinsic buffer a-Si:H(n/i) layers. Control of doping concentration of the amorphous layer is essential to gain sufficient conductivity and junction potential while avoiding an increase in defect density of the a-Si:H(n) layer. Inserting a-Si:H(i) provides high passivation quality by reducing a-Si:H/c-Si interface recombination and leads to a higher open circuit voltage. Properties and thicknesses of both a-Si:H(n) and a-Si:H(i) have a significant role on the performance of silicon heterojunction cell. In this paper, emitter a-Si:H(n) and buffer a-Si:H(i) layers thicknesses are optimized at the optimum gas phase doping concentration in order to obtain high efficiencies.

[1]  Steven S. Hegedus,et al.  Thin‐film solar cells: device measurements and analysis , 2004 .

[2]  J. Werner,et al.  Recombination mechanisms in amorphous silicon/crystalline silicon heterojunction solar cells , 2000 .

[3]  Wyatt K. Metzger,et al.  The role of amorphous silicon and tunneling in heterojunction with intrinsic thin layer (HIT) solar cells , 2009 .

[4]  Ralf B. Bergmann,et al.  Optimization and characterization of amorphous/crystalline silicon heterojunction solar cells , 2002 .

[5]  Makoto Tanaka,et al.  Twenty-two percent efficiency HIT solar cell , 2009 .

[6]  R. Stangl,et al.  Advances in a-Si:H/c-Si heterojunction solar cell fabrication and characterization , 2009 .

[7]  B. To,et al.  Efficient heterojunction solar cells on p-type crystal silicon wafers , 2010 .

[8]  Mario Tucci,et al.  17% Efficiency heterostructure solar cell based on p-type crystalline silicon , 2004 .

[9]  R. Scheer,et al.  Interface recombination in heterojunction solar cells: Influence of buffer layer thickness , 2011 .

[10]  Makoto Tanaka,et al.  Development of New a-Si/c-Si Heterojunction Solar Cells: ACJ-HIT (Artificially Constructed Junction-Heterojunction with Intrinsic Thin-Layer) , 1992 .

[11]  L. Korte,et al.  Heterojunctions of hydrogenated amorphous silicon and monocrystalline silicon , 2006 .

[12]  M. Schmidt,et al.  Efficient silicon heterojunction solar cells based on p‐ and n‐type substrates processed at temperatures < 220°C , 2006 .

[13]  Qi Wang,et al.  High-efficiency hydrogenated amorphous/crystalline Si heterojunction solar cells , 2009 .

[14]  W. Metzger,et al.  Device Physics of Heterojunction with Intrinsic Thin Layer (HIT) Solar Cells , 2009 .

[15]  M. Tucci.  Optimization of n-doping in n-type a-SI : H/p-type textured c-Si heterojunction for photovoltaic applications , 1999 .

[16]  V. Yelundur,et al.  Effective interfaces in silicon heterojunction solar cells , 2005, Conference Record of the Thirty-first IEEE Photovoltaic Specialists Conference, 2005..

[17]  C. Ballif,et al.  >21% Efficient Silicon Heterojunction Solar Cells on n- and p-Type Wafers Compared , 2013, IEEE Journal of Photovoltaics.

[18]  Weiqi Wang,et al.  Design optimization of bifacial HIT solar cells on p-type silicon substrates by simulation , 2008 .

[19]  D. Borchert,et al.  Preparation of (n) a-Si: H/(p) c-Si heterojunction solar cells , 1997 .

[20]  D. Pysch,et al.  Analysis and optimization approach for the doped amorphous layers of silicon heterojunction solar cells , 2011 .

[21]  R. Crandall,et al.  Amorphous/crystalline silicon heterojunction solar cells with varying i-layer thickness , 2011 .

[22]  P. Cabarrocas,et al.  Criteria for improved open-circuit voltage in a-Si :H(N)/c-Si(P) front heterojunction with intrinsic thin layer solar cells , 2008 .

[23]  R. Schropp,et al.  Role of the buffer layer in the active junction in amorphous-crystalline silicon heterojunction solar cells , 2000 .

[24]  Makoto Tanaka,et al.  Obtaining a higher Voc in HIT cells , 2005 .

[25]  S. Glunz,et al.  Improving the a-Si:H(p) rear emitter contact of n-type silicon solar cells , 2012 .

[26]  L. Korte,et al.  Electronic states in a-Si:H/c-Si heterostructures , 2006 .

[27]  M. Schmidt,et al.  Optimization of Interface Properties in a-Si:H/c-Si Heterojunction Solar Cells , 2006, 2006 IEEE 4th World Conference on Photovoltaic Energy Conference.

[28]  L. Korte,et al.  Investigation of gap states in phosphorous-doped ultra-thin a-Si:H by near-UV photoelectron spectroscopy , 2008 .

[29]  U. Das,et al.  Surface passivation and heterojunction cells on Si (100) and (111) wafers using dc and rf plasma deposited Si:H thin films , 2008 .

[30]  H. Fujiwara,et al.  Impact of epitaxial growth at the heterointerface of a-Si:H∕c-Si solar cells , 2007 .

[31]  P. Cabarrocas,et al.  Toward a better physical understanding of a-Si:H/c-Si heterojunction solar cells , 2009 .