1. Surface Passivation of Crystalline Silicon Solar Cells: A Review Armin G. Aberle Progress in Photovoltaics: Research and Application 8,473-487,2000.

2. 2010/8/27 2/5 NCTU IEO GPL Outline  Introduction  Fundamental physics  Surface passivation method  Surface passivation of c-Si solar cells

3. 2010/8/27 3/5 NCTU IEO GPL Introduction  Defects Extrinsic (Processing related) Intrinsic (Si related, unavoidable)  Dangling bond Growth condition Dislocation

4. 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

5. 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:

6. 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)

7. 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)

8. 2010/8/27 8/5 NCTU IEO GPL Combined passivaction

9. 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 3 ++++++++++++ ------------ e-e- h+

10. 2010/8/27 10/5 NCTU IEO GPL PERL solar cells  Passivated Emitter and Rear Locally Diffused Solar Cell (24.7%)

11. 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.

12. Thanks for your attention!!