An amorphous SiC/Si two-color detector

A glass/ITO/(n
⁺
-i) a-SiC:H/(p
⁺
-i-n
⁺
) a-Si:H/A1 photodetector with a voltage-selectable spectral response was fabricated successfully. It consists of two back-to-back p-i-n junctions, including an a-SiC:H/a-Si:H heterojunction and a-Si:H homojunction. As the bias at the ITO side changes from 2 to -2 V, the responsivity to light with a wavelength of 6000 Å increases 18 times, whereas for light of 4500 Å, it decreases three times. The detectivity ratio at these two wavelengths then changes from 0.16 to 4 which provides a good distinction between two colors, i.e., orange and blue.