Back Amorphous-crystalline Silicon Heterojunction Photovoltaics: Fabrication Methodology

• Main Author: Hertanto, Anthony Iman
• Other Authors: Kherani, Nazir P.
• Language: en_ca
• Published: 2009
• Subjects: Photovoltaic; Solar Cell; Back contact; Heterojunction; BACH; Silicon PV; 0544
• Online Access: http://hdl.handle.net/1807/18322

Back Amorphous-Crystalline silicon Heterojunction (BACH) solar cells which combine the benefits of back contact and heterojunction silicon solar cells have been fabricated at the University of Toronto. p- and n-type amorphous silicon deposited at low temperature (~<200 oC) by DC Saddle-Field PECVD system forms interdigitated hetero-emitter and base contacts on the rear-side. A photolithography approach using thermal oxide for electrical isolation demonstrates the proof-of-concept. Three methods for fabricating simplified and advanced BACH cells were explored. The best performing 1 cm2 cell showed an AM1.5G conversion efficiency of 8.11%, VOC = 0.536 V, JSC = 20.1 mA/cm2 and FF = 75.5%. The BACH cell performance is limited by poor surface passivation and un-optimized cell design. With completely low temperature processing, highly passivated front and rear surfaces, and independent optimization of front-side optical antireflective features and rear-side electrical junctions and contacts, the BACH cell has the potential of becoming highly cost competitive.