Abstract
Large-grained (5-20 ..mu..m) polycrystalline silicon layers have been grown at intermediate temperatures of 750?-950?C directly on foreign substrates without a seeding layer by iodine vapor transport at atmospheric pressure with rates as high as 3 mm/min. A model is constructed to explain the atypical temperature dependence of growth rate. We have also used this technique to grow high-qualityepitaxial layers on heavily doped CZ-Si and on upgraded MG-Si substrates. Possible solar cell structures of thin-layer polycrystalline silicon on foreign substrates with light trapping have been examined, compared, and optimized by two-dimensional device simulations. The effects of grain boundary re-combination on device performance are presented for two grain sizes of 2 and 20 mm. We found that104 cm/s recombination velocity is adequate for 20-m m grain-sized thin silicon, whereas a very low recombination velocity of 103 cm/s must be accomplished in order to achieve reasonable performance for a 2-mm grain-sized polycrystalline silicon device.
Original language | American English |
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Number of pages | 7 |
State | Published - 2002 |
Event | 29th IEEE PV Specialists Conference - New Orleans, Louisiana Duration: 20 May 2002 → 24 May 2002 |
Conference
Conference | 29th IEEE PV Specialists Conference |
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City | New Orleans, Louisiana |
Period | 20/05/02 → 24/05/02 |
Bibliographical note
Prepared for the 29th IEEE PV Specialists Conference, 20-24 May; 2002, New Orleans, LouisianaNREL Publication Number
- NREL/CP-520-31441
Keywords
- atmospheric pressure iodine vapor transport (APIVT)
- epitaxial layers
- grain boundary (GBS)
- microcrystalline silicon
- PV
- recombination velocity
- single junction
- solar cells
- two-dimensional device