Innovative Optoelectronic Approaches to Biomolecular Analysis with Arrays of Silicon Devices

a-Si:H Metal-Semiconductor-Metal (MSM) Photoconductor Detector for Biomolecular Imaging Applications

“…However, the presence of carbon in the silicon network tends to increase the density of states. Thus, a lower quality film was obtained that offsets spectral selectivity and the best responsivity reported (using very thin p+ contact layers of 5 nm) was 0.045 A/W at wavelengths < 300nm (12).…”

“…Selective ultraviolet (UV) wavelength detectors are attractive for emerging fields in biomedical applications: for example, a-Si:H sensors have been reported to detect the variation of DNA absorbance of UV (7) with specific application to genome projects (10,11) such as DNA fragment sizing, DNA sequencing, and amino acid analysis. The performance of a UV detector at a wavelength of 260 nm is critical because DNA significantly absorbs at this wavelength (12). In order to improve signal-to-noise ratios (SNR), the responsivity of the detector at 260 nm must be high while suppressing responsivity at other wavelengths.…”

“…However, pin photodiodes using a-Si:H material have been reported to show a two-fold sensitivity improvement over GaAsP Schottky diodes in the UV region with a peak responsivity of 254 mA/W at 385nm (14). To date, different pin photodiode configurations with varying thickness of hydrogenated amorphous silicon carbide, a-SiC:H have also been reported for UV detection (12,13). The wider bandgap of a-SiC:H shows higher selectivity to short wavelengths in the visible spectrum.…”