a-SiC:H thin film solar cells

• Main Authors: Da-Jhe Huang, 黃大哲
• Other Authors: Yeu-Long Jiang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/4bd5ev

碩士 === 國立中興大學 === 電機工程學系所 === 101 === In this thesis, hydrogenated amorphous silicon carbide (a-SiC:H) thin-film solar cells were prepared by using 13.56 MHz pulse-modulation plasma-enhanced chemical vapor deposition (Pulse-PECVD). (1) Modulation of plasma turn-on time (ton) to fabricate single i-layer, (2) inserting buffer layers at the p/i and i/n interfaces, and (3) step change ton to prepare graded bandgap (Eg) i-layer, using these experimental design, the influence of different bandgap single i-layer, buffer layers, and graded bandgap i-layer on the performance of a-SiC: H solar cells were investigated. For pulse modulation of ton to produce the single i-layer a-SiC: H with various Eg solar cells, as ton changes from 5 ms to 40 ms, the deposition rate is increased from 0.046 nm/s to 0.199 nm/s, and the Eg is increased from 1.70 eV to 1.765 eV. The absorption coefficient and the density of the film were decreased. The open-circuit voltage (Voc) of the solar cells is increased from 0.822 V to 0.872 V, but short-circuit current density (Jsc) is decreased from 11.91 mA/cm2 to 10.24 mA/cm2, and fill factor (FF) is also decreased from 72.8 % to 66.5 %. Due to the reduction of Jsc and FF, the energy transfer efficiency is decreased from 7.12% to 5.94%. For insertion of a thin (15 nm) a-SiC:H buffer layer at p/i interface, as ton increases from 10 ms, to 20 ms and to 40 ms, the Voc and FF are increased.The performance of a-SiC: H solar cell can be improved with the Voc, Jsc, FF, and energy transfer efficiency f 0.837 V, 11.87 mA/cm2,73.7%, and 7.32 %.For insertion of a thin (15nm) a-SiC: H buffer layer at i/n interface, as ton increases from 5 ms,to 10 ms, and to 20 ms, the Voc,Jsc, and FF are decreased. The performance of a-SiC: H solar cell can be improved with the Voc, Jsc, FF, and energy transfer efficiency of 0.86 V, 10.41 mA/cm2,70.1 %, and 6.72 %. For step change ton to prepare graded bandgap a-SiC:H i-layer solar cells, the graded bandgap solar cell has the effective Eg of 1.732 eV, that the Jsc and FF relative to those of the i-layer with the Eg of 1.765 eV solar cell are increased from 10.41 mA/cm2 to 11.19 mA/cm2,and 70% to 71.7%, but are not higher than the i-layer with the Eg of 1.70 eV solar cell, which the Jsc and FFare 11.87 mA/cm2 and 73.7%. The Voc of graded bandgap solar cell relative to that of the i-layer with the Eg of 1.70 eV solar cellis increased from 0.837 V to 0.860 V, which is very close tothe value (0.862V) of i-layer with the Egof 1.765 eV solar cell. The energy transfer efficiency of graded bandgap solar cell with respect to the i-layer with the Eg of 1.765 eV solar cell is increased from 6.27% to 6.90%, but is not higher than the value (7.32%) of the i-layer with the Eg of 1.70 eV solar cell.