Surface Passivation of Crystalline Silicon Solar Cells: A Review Armin G. Aberle Progress in Photovoltaics: Research and Application 8, ,2000.
2010/8/27 2/5 NCTU IEO GPL Outline Introduction Fundamental physics Surface passivation method Surface passivation of c-Si solar cells
2010/8/27 3/5 NCTU IEO GPL Introduction Defects Extrinsic (Processing related) Intrinsic (Si related, unavoidable) Dangling bond Growth condition Dislocation
2010/8/27 4/5 NCTU IEO GPL Surface type in Si solar cell Metalized Finger and bus bar Very high surface recombination Avoid recombination loss Non-metalized Illuminated region Well passivated and good blue response Avoid highly doped Back electrode high surface recombination Avoid recombination loss
2010/8/27 5/5 NCTU IEO GPL Surface recombination Shockley-Read-Hall (SRH) theory Low recombination rate strategy 1. low surface state N st 2. low carrier concentration n s, p s EtEt EcEc EvEv Surface Recombination rate:
2010/8/27 6/5 NCTU IEO GPL Reduction of the surface states Growth/deposition of a dielectric film SiO 2 Al 2 O 3 SiN x Antireflective coating layer Chemical methods HF immersion Alcoholic solution Si solar cell Dielectric layer(d)
2010/8/27 7/5 NCTU IEO GPL Field-effect passivated High-low junction p + -p n + -n Back surface field (BSF) Front surface field (FSF) p-n junction MIS Selective emitter HIT(a-Si)
2010/8/27 8/5 NCTU IEO GPL Combined passivaction
2010/8/27 9/5 NCTU IEO GPL Concept The fixed charge induced the negative charge on the surface, bending the band diagram. Al 2 O 3 is suitable to p-type Si substrate. Al 2 O e-e- h+
2010/8/27 10/5 NCTU IEO GPL PERL solar cells Passivated Emitter and Rear Locally Diffused Solar Cell (24.7%)
2010/8/27 11/5 NCTU IEO GPL Band offset measurement The Si substrate can passivated by dielectric film and electric field effect method. The Al 2 O 3 is suitable for p-type Si substrate passivation, and the SiN x is suitable for n-type Si substrate passivation.
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