| 학회 | 한국재료학회 |
| 학술대회 | 2013년 봄 (05/23 ~ 05/24, 여수 엠블호텔(THE MVL)) |
| 권호 | 19권 1호 |
| 발표분야 | 제24회 신소재 심포지엄-The 2nd International Symposium on Green Energy 2013 |
| 제목 | Si Thin Film Photovoltaic Technology |
| 초록 | Low temperature a-SiGe:H with controllable optical band-gap (from 1.7~1 eV) [1] and high absorption coefficient is an attractive candidate material for NIR sensors and photovoltaic devices on low-cost and light weight flexible substrates [2-4]. The optical band-gap of hydrogenated amorphous a-SiGe:H can be easily controlled by changing the alloy composition. However, a-SiGe optoelectronics fabricated by RF Plasma-Enhanced CVD (RFPECVD) using SiH4 and GeH4 precursors at low deposition temperature showed poor Near-IR photo response and poor light-soaking stability, even the optical band gap of a-SiGe:H below 1.5eV. This is due to much different dissociation rate of SiH4 and GeH4 precursors in RF-PECVD at low deposition temperature lead to high Ge content a-SiGe absorption films with low mass density, high defect density and poor electrical properties. Inductively coupled plasma chemical vapor deposition (ICP-CVD) system [5-6], because of its high fractional ionization capacity, can produce high-density plasma to improve diffusion of the reactive radicals on substrates even at fairly low deposition temperatures. The configuration of ICP system with high density plasma separated from the thin film growing region effectively reduces the possibility of ion bombardment on growing surface, resulting in a film with low density of defects. In this study, we reported a-Si/a-SiGe tandem solar cell fabricated at low temperature (140oC) using ICPCVD with Si2H6 and GeH4 precursors which possess similar dissociation rate. a-Si/a-SiGe tandem solar cell shows conversion efficiency as high as 8.38% with only 5% degradation. This low thermal-budget thin-film technique could open up the feasibility of flexible solar self-powered multi-functional panel and 3D stacked monolithic devices. References [1] S. Aljishi et al., in Mat. Res. Symp. Proc., vol. 70,p. 269(1986). [2] A. Catalano et al., J. Non-Cryst. Solids, vol. 115, p.14 (1989); [3] S. D. Liu et al., IEEE Trans. Electron Devices,vol. 48, p. 1564 ( 2001); [4] S.Y.Han et al., J. Soc. Inf. Display, vol. 19, p.855( 2011); [5] C.‐H. Shen et al., IEEE IEDM, p.700 (2010); [6] C.‐H. Shen et al., Appl. Phys. Lett. 99, 033510 (2011). Figure 1. Schematic diagram of a-Si/a-SiGe tandem solar cell. Figure 2.J-V characteristics of a-Si/a-SiGe tandem solar cell using Si2H6 precursor with and without buffer layers. Figure 3. Quantum efficiency of a-Si/a-SiGe tandem solar cell using Si2H6 precursor with and without buffer layers. |
| 저자 | Chang Hong Shen1, Ming-Hsuan Kao2, Peichen Yu3, Hao-Chung Kuo4, Ching-Ting Lee2, Jia-Min Shieh3 |
| 소속 | 1national Nano Device Laboratories, 2Hsinchu, 3Taiwan, 4National Chiao Tung Univ. |
| 키워드 | a-SiGe; tandem solar cell; conversion efficiency; ICPCVD |
