Study of growing zinc oxide on polycrystalline silicon/glass substrate prepared by aluminum-induced crystallization of amorphous silicon

Zinc oxide (ZnO) was grown on a polycrystalline silicon (pc-Si)/glass substrate prepared by the aluminum-induced crystallization (AIC) of amorphous silicon. ZnO directly grown on the AIC-pc-Si exhibits many defects with a distribution unlike that of conventional ZnO; the defect density is highest near the conduction band and decreases near the valence band. The defects can be greatly suppressed by depositing an epitaxial silicon (Epi-Si) layer on the AIC-pc-Si. The resulting defect distribution is similar to that of ZnO grown on a crystalline Si (c-Si) substrate. X-ray diffraction shows that the epitaxial silicon layer can improve the crystallization of ZnO. However, the AIC-pc-Si and Epi-Si/AIC-pc-Si substrates exhibit rougher surfaces; consequently, the ZnO has a more random structure and lower density than that grown on a c-Si substrate. X-ray photoelectron spectroscopy demonstrates that as compared to the ZnO grown on the AIC-pc-Si, the defect ratio could be dramatically reduced from 0.70 to 0.56 by depositing an epitaxial silicon layer on AIC-pc-Si, and the defect ratio is about the same as that (0.55) for the ZnO grown on a c-Si substrate.