Three-dimensional Dirac semimetal (Cd1−xZnx)3As2/Sb2Se3 back-to-back heterojunction for fast-response broadband photodetector with ultrahigh signal-to-noise ratio

Three-dimensional (3D) Dirac semimetal materials have great application prospects in broad-spectrum photodetectors (PDs) working at wavebands up to the mid/far infrared region owing their unique topological energy-band architectures and excellent photoelectric properties. However, relatively high dark current most semimetal-based PDs limits photodetection performance, with poor signal-to-noise ratios (SNRs). Herein, we developed an ultra-low-noise-level PD linear array based on a 3D (Cd1−xZnx)3As2/Sb2Se3 back-to-back (BTB) heterojunction using molecular beam epitaxy (MBE)-grown (Cd1−xZnx)3As2 film. Benefiting from effective double-heterojunction design strategy, as-fabricated linear-array exhibited outstanding capacity visible mid-infrared (450 nm 4.5 µm), highest recorded SNR close 104, peak specific detectivity of 5.2 × 1012 Jones, response speed about 87.5 µs room temperature. Furthermore, long-term stability uniformity as only minor photocurrent fluctuations occurred among different units demonstrating feasibility for advanced optoelectronic applications, such real-time light trajectory tracking. This work provides reference strategy fabrication fast-response broadband ultrahigh SNRs BTB demonstrates prospect manufacture uncooled focal-plane-array devices.