A study on the improvement of amorphous silicon/crystalline silicon heterojunction solar cells by microwave processing

The postdeposition microwave heating treatment is carried out on the n-type crystalline silicon with bifacial deposited intrinsic hydrogenated amorphous silicon layers (i/c-Si/i) used as a precursor for amorphous silicon/crystalline silicon heterojunction (SHJ) solar cells. The passivation of i/c-Si/i heterostructure was improved significantly in 5 s microwave processing and two cycles of this processing later it could be stabilized. The results of FTIR show that the hydrogen within (i)a-Si:H layer is released rapidly during the process and the microstructure factor R* continues to decrease versus the processing time. An appropriate amount of hydrogen atoms released from Si–H bonds (especially weak bonds) move to the interface to saturate the dangling bonds favoring the passivation performance but excessive hydrogen release from the layers could lead to extremely poor passivation. The SHJ solar cell with a microwave-treated precursor of i/c-Si/i achieved an improved efficiency of 1.6