High-performance, ultra-broadband Sb2Te3 photodetector assisted by multimechanism

Abstract

Ultra-broadband spectral detection is critical for the application of several technologies, such as imaging, sensing, spectroscopy, and communication. However, the development of high-performance photodetectors with a wide spectral response remains a significant challenge. In this study, we present an ultra-broadband, responsive, dual-mechanism fusion photodetector based on the topological insulator Sb2Te3. By employing methods such as applying bias voltages, energy band structures, and photocurrent imaging, we have confirmed that the operating mechanism in the visible to the infrared light region is the photoconductive effect, exhibiting a room-temperature responsivity of 114.6 mA/W and a specific detectivity of 1.78 × 108 cm2 Hz1/2 W−1, especially under the working condition of 520 nm. Moreover, extending the spectral detection capability from infrared to terahertz is critically important. In the terahertz range, where photon energies are significantly lower than those in the visible to infrared spectrum, the detector achieves a room-temperature responsivity of 38.5 mA/W at 0.12 THz and a specific detectivity of 3.44 × 1010 cm2 Hz1/2 W−1, with a response time of 20 µs, primarily attributed to the asymmetric scattering behavior of the topological surface states. Notably, we have successfully demonstrated high-resolution imaging in the visible to infrared and terahertz spectral ranges at room temperature, providing strong evidence of practical applications for our photodetector. In conclusion, Sb2Te3, as an emerging broadband photodetection material, exhibits significant potential and lays a robust foundation for further research in the field of ultra-broadband photodetectors.