Interface states study of intrinsic amorphous silicon for crystalline silicon surface passivation in HIT solar cell

摘要

Intrinsic hydrogenated amorphous silicon (a-Si∶H) film is deposited on n-type crystalline silicon (c-Si) wafer by hotwire chemical vapor deposition (HWCVD) to analyze the amorphous/crystalline heterointerface passivation properties.The minority carrier lifetime of symmetric heterostructure is measured by using Sinton Consulting WCT-120 lifetime tester system,and a simple method of determining the interface state density (Dit) from lifetime measurement is proposed.The interface state density (Dit) measurement is also performed by using deep-level transient spectroscopy (DLTS) to prove the validity of the simple method.The microstructures and hydrogen bonding configurations of a-Si∶H films with different hydrogen dilutions are investigated by using spectroscopic ellipsometry (SE) and Fourier transform infrared spectroscopy (FTIR) respectively.Lower values of interface state density (Dit) are obtained by using a-Si∶H film with more uniform,compact microstructures and fewer bulk defects on crystalline silicon deposited by HWCVD.