Cu(In,Ga)Se2 thin-film photosensors

Photovoltaic sensors with a Cu(In,Ga)Se-2 (CIGS) thin film, a promising material for use in radiation-hardened space devices, have been investigated for the first time. Linear light-current characteristics were observed for the CIGS photosensors under illumination intensities ranging from 1 to 10(3) lux. The photoresponse time was measured to be approximately 3 mu s, which is comparable to that of crystalline silicon pn junction and amorphous silicon pin junction photosensors. However, the reverse saturation current was relatively large, 10(-7) A/cm(2), in the present experiment. The spectral response was observed in the wavelength range of 400-1,200 nm, suggesting that this device may be utilized as a photosensor with a wide spectral response.