Abstract
Self-powered, wide-spectral response, fast, and high-sensitivity photodetectors are essential for developing next-generation optoelectronic devices. In this work, the predicted optoelectronic properties of the ternary metal-zinc (Zn)-nitride (N) thin films are experimentally demonstrated. A novel phase of the Titanium (Ti)-Zn-N system (dominantly TiZnN2 film of ≈235 nm thickness) is developed on the p-Si substrate, which shows excellent optoelectronic properties. The Indium Tin Oxide (ITO)/TiZnN2/p-type Si (p-Si) photodetector of area ≈4 mm2 exhibits an impressive responsivity of 1.22 × 10–4 A W−1 at 0 V and 40 mA W−1 at −4 V, a specific detectivity up to 1.16 × 109 Jones at 0 V, and a response speed of 1.9 ms at zero external bias (i.e., self-powered mode). Benefiting from the broad-band absorption of the film and p-Si combination, the detection range is observed from the ultraviolet to near-infrared (300–1150 nm). Simultaneous operation of self-powered photo-triggered drip irrigation ON and street light OFF in the early morning and vice-versa in the evening is demonstrated for autonomous farming. The device is insensitive to humidity and ambiance, and generates a photocurrent with light intensity as low as 5 mW cm−2. The active layer is hydrophobic and highly stable, and the fabrication is cost-effective.
