Efficiency improvement of a-Si:H Thin-Film Solar Cells by phosphorus doping of absorption layer with a-Si:H buffer layer at p/i interface

• Published in: Molecular Crystals and Liquid Crystals 2018-11, Vol.676 (1), p.131-140
• Main Authors: Son, Won Ho, Lee, Si-Hun, Kim, Jae Keon, Choi, Sie Young, Kong, Seong Ho, Jung, Daewoong
• Format: Article
• Language: English
• Subjects: Amorphous materials; Amorphous silicon; Buffer layers; Circuits; conductivity; Flow rates; Flow velocity; light doping; Open circuit voltage; Organic chemistry; PECVD; Phosphorus; Photovoltaic cells; pin-type a-Si:H solar cell; Plasma enhanced chemical vapor deposition; Short circuit currents; Solar cells; Thickness; Thin films
• ISSN: 1542-1406; 1563-5287; 1527-1943
• DOI: 10.1080/15421406.2019.1596229

Comparative properties of pin-type amorphous silicon (a-Si:H) thin-film solar cells with different PH 3 flows for the i-layer and the presence of a buffer layer at the p-i interface were investigated. Doped a-Si:H films with different PH 3 concentrations were fabricated by mixing PH 3 , SiH 4 , and H 2 during i-layer deposition. The flows were changed within 0-4.2 sccm, the total thickness of the buffer and intrinsic layers was 200 nm, and the thickness of the buffer layer was varied from 0-30 nm. All amorphous materials on films were deposited by a plasma-enhanced chemical vapor deposition method. Output performances (open-circuit voltage V oc , short-circuit current density J sc , fill factor FF, and conversion efficiency η) of the solar cells were characterized to optimize the structural features and manufactural processes. The maximum values of parameters were measured at a PH 3 flow of 0.9 sccm. Excessive or insufficient flow rates of PH 3 will deteriorate the solar cell characteristics because of the resulting large defect density and increased recombination rate, respectively. Performance of solar cells with the a-Si:H buffer layer (V oc = 0.682V, J sc = 17.21 mA/cm 2 , FF = 0.51, and η = 6.03) improved compared with the results where phosphorus was lightly doped on the i-layer of pin-type a-Si:H solar cells without a buffer layer (V oc = 0.655 V, J sc = 17.08 mA/cm 2 , FF = 0.46, and η = 5.11).