  Mid-infrared spectrum is a critical tool for chemical analysis, industrial
inspection, environment, and other fields due to its rich chemical bond
information. However, the complicated growth or fabrication procedures of
existing mid-infrared sensitive materials hinder the large-scale production and
utilization of mid-infrared detectors. To address this issue, we developed Si:S
barrier detectors employing sulfur doped silicon and a sophisticated band
barrier design. Since the transport of dark current and photo current is
separated, the barrier design effectively suppresses the dark current while
allowing the photo current to leverage gain mechanisms, thereby substantially
improving signal-to-noise ratio. As a result, the detector exhibits an infrared
response range covering from 1.12 to 4.4{\mu}m with a peak at 3.3{\mu}m,
excluding its intrinsic response in visible range. Its peak quantum efficiency
surpasses that of the best mid-infrared silicon-based detector reported to date
by an order of magnitude, reaching 2% at room temperature. The peak detectivity
at 90K is 1.4E11 Jones @1.4V and decreases to 4.4E9 Jones @1.4V, 210K,
comparable to the typical III-V and IV-VI photodetectors at one thousandth
fabrication cost. Leveraging the well-established silicon-based manufacturing
process, this device holds promise for large-scale production at a reduced
price, offering a cost-effective solution for future mid-infrared detection.
