Effects of tunneling oxide defect density and inter-diffused carrier concentration on carrier selective contact solar cell performance: Illumination and temperature effects

• Published in: Solar energy Vol. 211; pp. 62 - 73
• Main Authors: Park, Cheolmin, Balaji, Nagarajan, Ahn, Shihyun, Park, Jinjoo, Cho, Eun-chel, Yi, Junsin
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 15-11-2020; Pergamon Press Inc
• Subjects: Amorphous silicon; CAD; Carrier density; Carrier selective contact; Computer aided design; Density; Diffusion layers; Electron selective contact; Environmental changes; Illumination; Illumination-temperature performance of solar cell; Open circuit voltage; Phosphorus; Photovoltaic cells; Plasma enhanced chemical vapor deposition; Solar cells; Solar energy; TCAD simulation; Temperature effects; Transmission electron microscopy; Tunnel oxide; Tunneling; X-ray spectroscopy; Electron selective contact; TCAD simulation; Tunnel oxide; Illumination-temperature performance of solar cell; Carrier selective contact
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2020.09.060

•Anneal temperature for layer formation effect on carrier inter-diffusion phenomenon.•TEM/EDS analysis at carrier selective contact layer/interface oxide/substrate.•Comparison of free energy loss analysis by inter-diffusion depth and concentration.•Comparison of the overall output performance by interface quality and inter-diffusion.•Output characteristics with illumination, temperature and interface quality change.
In this study, technology computer-aided design (TCAD) was used to investigate carrier selective contact solar cell performance based on the boundary of tunneling oxide and electron selective contact layer properties. The role of tunneling oxide quality in the passivation and inter-diffusion properties of the plasma-enhanced chemical vapor deposition of phosphorus-doped amorphous silicon as an electron selective contact layer is studied for carrier selective contact solar cells. Tunnel oxide quality varies according to the ratio of Si4+ to Si2+ state. For the Si4+/Si2+ ratio of 4, open-circuit voltage of 730 mV and the lowest interface trap density of 5.3 × 1010 cm−2 eV−1 are achieved. The change in diffusion depth of the doped layer with respect to the annealing temperature is analysed by transmission electron microscopy (TEM)/energy dispersive X-ray spectroscopy (EDS) measurement. Carrier selective contact solar cell parameters are optimized by incorporating the experimental values of interface trap density, inter-diffused impurity concentration, and depth in the Quokka 3 TCAD tool. Solar cell conversion efficiency of 24.31% was obtained. To understand the response of carrier selective solar cell to the environmental changes, the output characteristics of the solar cell were studied by varying the illumination temperature by 10% of the standard test conditions (STC) and temperature from 277 K to 377 K (difference of 100 K).