The amorphous SiC/Si two and three-color detector with high rejection ratio

Two and three-color a-SiC:H/a-Si:H heterojunction photodetectors modified from previously published two-color detector to improve rejection ratio at peak responses have been fabricated. Modified two-color detector improves the rejection ratio of blue response at 450 nm from 2.5 to 8 by incorporating a 50 nm a-Si:H layer into the collector. Three-color detector further separate green and red responses by using two a-Si:H layers deposited at different conditions in the emitter junction. The measured responsivity of three-color detector shows three responses with peaks at λ = 480, 530 and 575 nm under bias of 2, -0.2 and -2 V, respectively, which are close to the responses of cone cells in our own eyes.