2D BP based mid-infrared Schottky junction photodetector

• Main Author: Wang, Kexin
• Other Authors: Wang Qijie
• Format: Thesis-Master by Coursework
• Language: English
• Published: Nanyang Technological University 2025
• Subjects: Engineering
• Online Access: https://hdl.handle.net/10356/182251
• Institution: Nanyang Technological University

With the growing research on two-dimensional materials, photodetectors have become one of the most commonly used technologies in various applications. They are used in areas such as human detection sensors for automatic doors, infrared thermal imaging devices in the military, high-precision non-contact temperature measurement in medical equipment, and image sensors in mobile phones and cameras. Photodetectors have become an essential part of daily life. As new materials with excellent optoelectronic properties continue to be discovered and studied, the manufacturing processes of new two-dimensional semiconductor devices are improving, leading to the development of more advanced photodetectors. These newly developed photodetectors offer better optoelectronic performance compared to traditional, larger-volume conductors. This includes features such as higher resolution, faster response times, and wider light detection ranges. Black phosphorus (BP), a direct bandgap semiconductor, has gained significant attention in the field of optoelectronic detection. Its bandgap ranges from 0.3 eV in bulk form to 1.8 eV in its monolayer form. BP has great potential as a core material for photodetectors, especially for use in visible and infrared light detection. In this work, we have studied the self-driven photoelectric response characteristics of an asymmetric Schottky junction photodetector made of two-dimensional BP and silver electrodes. Our research offers new perspectives and methods for developing self-driven mid-infrared photodetectors. We evaluated the performance of the self-driven photodetector based on two-dimensional black phosphorus. The device demonstrated excellent repeatability and high stability in its light response. Under 3600 nm illumination, it achieved a responsivity of 11 mA/W and a detectivity of 2.1x10^8 Jones. Additionally, the device exhibited a noticeable photovoltaic effect under zero bias voltage, confirming its self-driven characteristics. The device also showed polarization sensitivity, allowing for the detection of polarized light.