Wafer-Scale Growth of Sb2Te3 Films via Low-Temperature Atomic Layer Deposition for Self-Powered Photodetectors

In this work, we demonstrate the performance of a silicon-compatible, high-performance, and self-powered photo detector. A wide detection range from visible (405 nm) to near infrared (1550 nm) light was enabled by the vertical p-n heterojunction between the p-type antimony telluride (Sb2Te3) thin film and the n-type silicon (Si) substrates. A Sb2Te3 film with a good crystal quality, low density of extended defects, proper stoichiometry, p-type nature, and excellent uniformity across a 4 in. wafer was achieved by atomic layer deposition at 80 degrees C using (Et3Si)2Te and SbCl3 as precursors. The processed photodetectors have a low dark current (similar to 20 pA), a high responsivity of (similar to 4.3 A/ W at 405 nm and similar to 150 mA/W at 1550 nm), a peak detectivity of similar to 1.65 x 1014 Jones, and a quick rise time of similar to 98 its under zero bias voltage. Density functional theory calculations reveal a narrow, near-direct, type-II band gap at the heterointerface that supports a strong built-in electric field leading to efficient separation of the photogenerated carriers. The devices have long-term air stability and efficient switching behavior even at elevated temperatures. These high-performance and self-powered p-Sb2Te3/n-Si heterojunction photodetectors have immense potential to become reliable technological building blocks for a plethora of innovative applications in next-generation optoelectronics, silicon-photonics, chip-level sensing, and detection.