A High-Detectivity, Fast-Response, and Radiation-Resistant TiN/CdZnTe Heterojunction Photodiode

Photodiodes have found wide practical applications as sensing and information transmission technology. However, some fields of their possible applications require added features besides excellent performance characteristics. For instance, the rapid development of commercial and scientific space programs and large-scale nuclear safety efforts in radioactively contaminated areas considerably demands next-generation radiation-resistant optoelectronic materials and devices. The heterojunction photodiode device concept opens a broad range of possibilities in combining different semiconductor materials with unique properties resulting in added functionalities, but with the price of detectivity and response time compared to conventional silicon photodiodes.<br/>In this work, we proposed a novel <i>high-performance and radiation-resistant</i> UV-vis-NIR (300 – 820 nm) heterojunction photodiode based on radiation-resistant functional semiconductor materials: titanium nitride (TiN) ‘window’ layer and cadmium zinc telluride solid solution (CdZnTe) photoactive layer. The developed TiN/CdZnTe heterojunction photodiodes <b>concurrently revealed outstanding detectivity <i>D</i>* = 4.14×10¹² Jones @ -0.2 V and rise/fall response times of 3.5/3.8 </b><b>μs @ -1.5 V</b> outperforming existing similar heterojunction optoelectronic devices based on photoactive compound semiconductor materials.[1] Moreover, the added feature of the proposed heterojunction photodiodes is their <b>advanced radiation resistance</b>, experimentally demonstrated under <i>extreme conditions</i> of short impulse proton irradiation (170 keV) with an accumulated fluence of 2 × 10¹² proton/cm². This unusual synergy of high performance and radiation resistance of the TiN/CdZnTe photodiodes is crucial for their reliable, long-term operation under the detrimental influence of ionizing radiation in extreme environments like space or radioactively contaminated zones.<br/>We have a strong belief that our work is of interest to a broad range of material scientists and device engineers, as it pushes the current detectivity-response time boundaries, defined by the long-standing materials science and device engineering problems in developing <b>simultaneously highly sensitive, fast-responding, and radiation-resistant optoelectronic devices</b> based on compound semiconductors.<br/><br/>[1] Mykhailo M. Solovan, Andriy I. Mostovyi, Hryhorii P. Parkhomenko, Marat Kaikanov, Nora Schopp, Ernest A. Asare, Taras Kovaliuk, Petr Vertat, Kostiantyn S. Ulyanytsky, Dmytro V. Korbutyak and Viktor V. Brus*, A High-Detectivity, Fast-Response, and Radiation-Resistant TiN/CdZnTe Heterojunction Photodiode, <i>Advanced Optical Materials</i> (in press).