Significance Short wave infrared detectors, as a very important type of detector, play a crucial role in sensing and obtaining target image information. Their notable features include the ability to penetrate smoke, high spatial recognition, all-weather working ability, and applicability in harsh weather conditions, making it widely applicable in multiple fields of national major needs and national economic development. In the military field, shortwave infrared detectors, with their unique night vision and covert reconnaissance functions, have become a key tool for enhancing combat capabilities at night and in adverse weather conditions. In the field of security monitoring, it provides strong technical support for video monitoring under low or no light conditions, significantly enhancing security capabilities. In terms of environmental monitoring, these detectors provide valuable data support for environmental protection and climate research by accurately measuring specific components in the atmosphere. In addition, in the medical field, the application of shortwave infrared detectors in disease diagnosis has opened up new paths for medical technology innovation. Therefore, in-depth research on shortwave infrared detectors has important practical significance.
Progress This article systematically reviews the photoelectric conversion mechanism of Schottky photodetector, and summarizes and analyzes recent research results at home and abroad around the basic physical processes of hot electrons. This article first introduces the formation and basic characteristics of metal silicon Schottky junctions, and explores the three core processes of hot electron generation, transmission, and injection. Next, in terms of the generation of hot electrons, a review is conducted on the relevant work of researchers to improve the efficiency of hot electron generation through methods such as light absorption enhancement and thermal loss suppression. In terms of the transfer of hot electrons, the current proposed methods to control the initial position, initial energy and momentum, and mean-free path of hot electrons have been summarized to improve the transfer efficiency of hot electrons. In the injection method of hot electrons, strategies to improve injection efficiency such as multiple Schottky junctions and interface engineering were introduced. In addition, considering the crucial impact of dark current on detector performance, this article also explores current methods for suppressing dark current. Finally, this article provides an outlook on the future development direction of this field.
Conclusions and Prospects Silicon-based hot electron detection technology holds the potential to broaden the response band of silicon to include the short-wave infrared band, while maintaining compatibility with silicon-based semiconductor processes. Its advantages, including low cost and high uniformity, bode well for its significant role in diverse fields such as military applications, security, and environmental monitoring. Looking ahead, it is imperative to delve deeper into the research of novel materials, structures, and mechanisms to further enhance the detector's performance. By focusing on developing new materials that can enhance the mean-free path of electrons and optimize the density of states, the transport efficiency of hot electrons can be boosted. Concurrently, the pursuit of innovative structures that efficiently absorb wide-spectrum infrared light, coupled with the optimization of the Schottky interface to increase hot electron injection efficiency and minimize dark current, is paramount. Moreover, exploring novel photoelectric conversion mechanisms that transcend the constraints of classical frameworks offers a promising avenue for pioneering advancements in infrared detection technology.
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