Fast-Response, Broadband Si-Based Photothermoelectric Photodetector Based on RF-Sputtering PbTe Film

Mid- and long-wave infrared photodetection is highly desired for various modern optoelectronic devices, but Si-based broadband photodetectors operating at room temperature remain challenging and are being extensively sought. In this paper, a Si-based photodetector with a broadband and fast photoresponse based on the photothermoelectric (PTE) effect of lead telluride (PbTe) film is demonstrated. Large-area, high-crystallinity PbTe film grown by a low-temperature, CMOS-compatible RF magnetron sputtering method is first reported for photodetection. The PbTe PTE photodetector surpasses the energy band gap limitation, operating even at wavelengths exceeding 10 μm. A rapid response time of less than 1 ms is obtained at 1310 nm, which is superior to those of most other reported PTE detectors. Furthermore, the development of a 5 × 5 array device shows a good photoresponse uniformity and demonstrates consistent mid-infrared imaging capabilities at room temperature. Excellent mechanical flexibility enables the integration of wearable optoelectronic devices. This pioneering research paves the way for significant advancements in Si-based broadband photodetector technologies, with potential applications in monolithic integrated detection and imaging systems that operate in visible- to long-wave infrared wavelengths at room temperature.