Abstract
n-Type beta-FeSi2/intrinsic-Si/p-type Si heterojunctions, prepared by facing-targets direct-current sputtering, were evaluated as near-infrared photodetectors. The built-in potential was estimated to be approximately 1 V from capacitance-voltage characteristics. Diodes with a junction area of 0.03 mm(2) exhibited a junction capacitance of 4.4 pF at zero bias. At room temperature, the devices exhibited responsivity of 140 mA/W and external quantum efficiency of 13% at a bias voltage of -5 V. The detectivity at zero bias was estimated to be 2.8 x 10(9) cm root Hz/W at the wavelength of 1.31 mu m. These results indicate their high application potential as near-infrared photodiodes integrated with Si. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3250171]