原子层沉积AlO_x薄膜对单晶硅太阳能电池钝化机制的影响

Passivation Mechanism of AlO_x Thin Film Fabricated on c-Si by Atomic Layer Deposition

采用原子层沉积设备在p型单晶制绒硅上制备了不同厚度的AlO_x薄膜。通过研究AlO_x薄膜厚度对样品的反射率、少数载流子寿命以及电容-电压特性的影响,发现沉积32 nm的AlO_x薄膜样品具有最好的钝化效果。另外,通过计算Si/AlO_x界面处的固定电荷密度和缺陷态密度,发现32 nm厚的AlO_x薄膜样品具有最低的缺陷态密度。系统研究了单晶硅材料的表面钝化机制,给出了影响样品载流子寿命的根本来源。

AlOx thin films with various thicknesses were fabricated on p-type textured crystalline silicon wafers through atomic layer deposition. The optical and electrical properties of MOx thin films were significantly improved by adjusting their thicknesses. The reflectance of MOx thin films decreased from 10. 12% to 0.96% with increasing thickness in a wide spectral range from 350 to 1 000 nm. The passivation effect of AlOx was discussed by using quasi steady state photo conductance （QSSPC） and capacitance-voltage （C-V） measurement. The AlOx thin film with the thickness of 32 nm shows the highest zoff and lowest interracial state density （Dit）. The origin of the polarity changing of the equivalent oxide charge （Qf） for the annealed AlOx thin film was also investigated.