P-silicon thin film fabricated by magnetron sputtering and aluminium induced crystallization for Schottky silicon solar cells

Solar cells consist of n-Si wafer and p-Si polycrystalline thin film, which was solely fabricated by magnetron sputtering, and aluminium induced crystallization, are presented in this paper. Firstly, the material and electrical properties of the fabricated p-Si thin films including the crystallization ratio, grain size, morphology, carrier density and mobility were studied by Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy and Hall Effect measurement, respectively. The p-Si polycrystalline thin film formed under optimal process conditions had the crystallization ratio of ~ 99% and the grain size of ~ 64.6 nm, determined from the data of Raman spectroscopy and XRD. The hole concentration in the fabricated p-Si polycrystalline thin films was mainly in the order of 1017 cm−3 to 1019 cm−3, and their corresponding mobility values ranged from 15 cm2/V s to 65 cm2/V s. Then solar cells with the device structure of Al electrode/n-Si wafer/p-Si thin film/Al electrode were fabricated, and their electrical properties were measured both under dark and illumination conditions by the semiconductor performance tester and solar simulator. The measured J-V curves under dark condition confirmed the creation of a p-n junction with the ideality factor of 1.55, rectification ratio of 410 at ± 1 V, and the reverse saturation current of 246 nA/cm2. The efficiency of 2.19%, with an open circuit voltage of 448 mV and a short circuit current density of 11.2 mA/cm2, was achieved under AM1.5G standard illuminations.