UV-Visible optical photo-detection from porous silicon (PS) MSM device

Si photodiodes have been in use as UV detectors and some compound semiconductors as visible detectors. However their implementation to the optoelectronic field is limited due to high fabrication cost and/or sophisticated prerequisites. The present article aims at fabricating porous silicon Metal-Semiconductor-Metal structure and its photodetection property for the UV wavelength range from 250 to 390 nm along with a portion of visible spectrum. PS thickness attained is ∼ 2 μm with uniform distribution of pores. It shows characteristic visible yellow/green luminescence under UV-Visible irradiation. The responsivities, obtained through photoconductivity measurement of the device, are obtained as 1.42 and 2.00 AW−1 for UV and visible ranges respectively, whereas the response times in corresponding ranges as 0.70 and 1.00 s. These results suggest superiority of the device as a UV-Visible detector compared to silicon or other semiconductor detectors. However, the device shows ageing effect due to slow oxidation of the PS layer.