Epitaxial n- and p-type Emitters for High Efficiency Solar Cell Concepts  

作　　者：Thomas Rachow Friedemann Heinz Bemd Steinhauser Stefan Janz Stefan Reber 

机构地区：[1]Fraunhofer ISE (Institute for Solar Energy Systems), Freiburg D-79110, Germany

出　　处：《Journal of Energy and Power Engineering》2014年第8期1371-1377,共7页能源与动力工程（美国大卫英文）

摘　　要：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.

关 键 词：Solar cells pn-junction emitter formation silicon deposition EPITAXY APCVD 

分 类 号：TN304.25[电子电信—物理电子学] TM914.4[电气工程—电力电子与电力传动]