Texturization of ZnO:Al surface by reactive ion etching in SF6/Ar, CHF3/Ar plasma for application in thin film silicon solar cells

As-deposited sputtered ZnO:Al (AZO) thin films having high transparency (T ≥ 85% at 550 nm of wavelength) and good electrical properties (ρ = 2.59 × 10−04 Ω cm) are etched to get suitable light trapping in thin film solar cells, using reactive ion etching method in sulfur hexafluoride–argon (SF6/Ar) plasma and trifluoromethane–argon (CHF3/Ar) plasma to texture their surface. Though the electrical properties of the films are not affected much by the etching process but significant increment in the average haze values in the wave length range of 350–1100 nm in the etched AZO films (19.21% for SF6/Ar and 22.07% for CHF3/Ar plasma etched) are found compared to as-deposited AZO films (5.61%). Increment in haze value is due to more scattering of light from the textured surface. These textured substrates are used as front transparent conducting oxide electrode for the fabrication of amorphous silicon solar cells. Solar cells fabricated on etched AZO substrates show 7.76% increase in conversion efficiency compared to as-deposited AZO substrates.

所沉积的溅射氧化锌铝（AZO）薄膜具有高透明度（在波长550 nm处，T≥85%）和良好的电学性能（ρ = 2.59×10⁻⁴ Ω·cm），为了在薄膜太阳能电池中实现合适的光捕获，使用六氟化硫 - 氩（SF₆/Ar）等离子体和三氟甲烷 - 氩（CHF₃/Ar）等离子体中的反应离子蚀刻方法对其表面进行纹理化处理。尽管蚀刻过程对薄膜的电学性能影响不大，但与所沉积的AZO薄膜（5.61%）相比，蚀刻后的AZO薄膜在350 - 1100 nm波长范围内的平均雾度值显著增加（SF₆/Ar蚀刻的为19.21%，CHF₃/Ar等离子体蚀刻的为22.07%）。雾度值的增加是由于纹理化表面对光的散射更多。这些纹理化的基底被用作制造非晶硅太阳能电池的正面透明导电氧化物电极。在蚀刻后的AZO基底上制造的太阳能电池与所沉积的AZO基底相比，转换效率提高了7.76%。