科研之友
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摘要
The purpose of this paper is to describe a very low-cost way to get low dark current metal-semiconductor-metal (MSM) photodetector. The application of cryogenic temperature treatment (77 K) at various cooling times (15-60 min) has been shown to significantly modify the surface properties of n-type silicon (100). Fresh monocrystalline n-type silicon (100) with a resistivity of 10-16 ohm-cm was used for the study. The Si was dipped in liquid nitrogen for 15 to 60 minutes at atmospheric pressure. The sample was folded in Al foil to avoid direct contact with liquid nitrogen. The surface roughnesses of the untreated and treated samples were determined by using AFM. The nickel (Ni) metal contacts were then deposited on the samples followed by current-voltage characterization (I-V). Optical properties of our samples were determined by Raman spectroscopy and XRD measurement at room temperature. Treated Si samples have better surface uniformity than untreated samples. The treated samples showed significant decrease in dark and light currents compared with the untreated samples. The current gain (ratio of photo to dark current) of some of the treated samples is enhanced whereas some are reduced compared with that of the untreated samples. The results showed that the treated samples have both higher Raman and XRD intensities than the untreated samples. This paper shows that it is possible to get smooth surface of silicon by using a simple and low-cost method of cryogenic temperature treatment and demonstrates potential MSM photodetector IV characteristics from the device.
- 出版日期2011-10
