Reducing the module prices by increasing the efficiency of solar cells is one of the major challenges in today＇s photovoltaic research. The emitter formation by epitaxial growth offers a cost-efficient and faster alt...Reducing the module prices by increasing the efficiency of solar cells is one of the major challenges in today＇s photovoltaic research. The emitter formation by epitaxial growth offers a cost-efficient and faster alternative to the standard furnace diffusion process. The efficiency potential of epitaxial emitters 〉 22% has already been proven using a single wafer, low pressure, chemical vapour deposition tool. The purpose of this work is to show the potential of epitaxially grown emitters by APCVD （atmospheric pressure chemical vapour deposition） compared to diffused emitters. The APCVD formation of epitaxial emitters at 1,050 ~C can be realised as high throughput inline process and only takes 1-2 min, whereas the diffusion process using POCI3 takes up to 60 min. Simulations show an increase in voltage of AVoc = ＋10 mV and a reduction in saturation current ,1o of 30% for the epitaxial emitter. The lifetime experiments of solar cells with epitaxial emitter exhibit a diffusion length Leff〉 750μm and an emitter saturation current of Joe 〈 50 fA/cm2 on a planar 10 Ω2cm p-type FZ wafer. Another important aim of this work is to evaluate the limitations of epitaxial emitters due to high thermal budget, interface recombination and the change of reflective properties on textured wafers due to the deposition process. Solar cell efficiencies up to 18.4% on p-type and 20.0% on n-type wafers presented in this paper underline that the emitter epitaxy by APCVD is a competitive process for the emitter formation.展开更多
对P型Cz-Si太阳能电池进行光致再生(LIR)测试,探寻抑制光致衰减(LID)效应的解决方案。选取A、B组电池样品各4片,在230℃下,A组分别采用[1,10,20,30]k W/m^2的光照功率进行10 s的LIR处理、B组采用20 k W/m^2的光照功率分别进行[10,20,30,...对P型Cz-Si太阳能电池进行光致再生(LIR)测试,探寻抑制光致衰减(LID)效应的解决方案。选取A、B组电池样品各4片,在230℃下,A组分别采用[1,10,20,30]k W/m^2的光照功率进行10 s的LIR处理、B组采用20 k W/m^2的光照功率分别进行[10,20,30,40]s的LIR处理;A、B组均在2 k W/m^2光照功率、85℃温度下进行10 H的LID测试,考察LIR后和LID后的电池转换效率相对变化值。随着光照功率的增大,LIR后的相对变化值由0.148%提升至0.792%,LID后的相对变化值由-2.608%改善至-0.396%,效果显著;随着光照时间的推移,LIR后的相对变化值由0.695%提升至0.939%,LID后的相对变化值由-0.794%改善至-0.395%,不甚显著。对现象成因进行讨论,表明高光照功率激发了电池硅基体内部的H^+、H^0和H^-,其中H^0和H^-存在的电子能够分别对硅基体内部和表面进行钝化,提升其少子寿命;H^+能够与B^-结合成BH复合体,阻碍BO复合体的生成,从而抑制电池的LID效应。展开更多
文摘Reducing the module prices by increasing the efficiency of solar cells is one of the major challenges in today＇s photovoltaic research. The emitter formation by epitaxial growth offers a cost-efficient and faster alternative to the standard furnace diffusion process. The efficiency potential of epitaxial emitters 〉 22% has already been proven using a single wafer, low pressure, chemical vapour deposition tool. The purpose of this work is to show the potential of epitaxially grown emitters by APCVD （atmospheric pressure chemical vapour deposition） compared to diffused emitters. The APCVD formation of epitaxial emitters at 1,050 ~C can be realised as high throughput inline process and only takes 1-2 min, whereas the diffusion process using POCI3 takes up to 60 min. Simulations show an increase in voltage of AVoc = ＋10 mV and a reduction in saturation current ,1o of 30% for the epitaxial emitter. The lifetime experiments of solar cells with epitaxial emitter exhibit a diffusion length Leff〉 750μm and an emitter saturation current of Joe 〈 50 fA/cm2 on a planar 10 Ω2cm p-type FZ wafer. Another important aim of this work is to evaluate the limitations of epitaxial emitters due to high thermal budget, interface recombination and the change of reflective properties on textured wafers due to the deposition process. Solar cell efficiencies up to 18.4% on p-type and 20.0% on n-type wafers presented in this paper underline that the emitter epitaxy by APCVD is a competitive process for the emitter formation.
文摘对P型Cz-Si太阳能电池进行光致再生(LIR)测试,探寻抑制光致衰减(LID)效应的解决方案。选取A、B组电池样品各4片,在230℃下,A组分别采用[1,10,20,30]k W/m^2的光照功率进行10 s的LIR处理、B组采用20 k W/m^2的光照功率分别进行[10,20,30,40]s的LIR处理;A、B组均在2 k W/m^2光照功率、85℃温度下进行10 H的LID测试,考察LIR后和LID后的电池转换效率相对变化值。随着光照功率的增大,LIR后的相对变化值由0.148%提升至0.792%,LID后的相对变化值由-2.608%改善至-0.396%,效果显著;随着光照时间的推移,LIR后的相对变化值由0.695%提升至0.939%,LID后的相对变化值由-0.794%改善至-0.395%,不甚显著。对现象成因进行讨论,表明高光照功率激发了电池硅基体内部的H^+、H^0和H^-,其中H^0和H^-存在的电子能够分别对硅基体内部和表面进行钝化,提升其少子寿命;H^+能够与B^-结合成BH复合体,阻碍BO复合体的生成,从而抑制电池的LID效应。
