Fast-Response Metal–Semiconductor–Metal Junction Ultraviolet Photodetector Based on ZnS:Mn Nanorod Networks via a Cost-Effective Method

Abstract

In this work, Mn2+-doped ZnS nanorods were synthesized by a facile hydrothermal method. The morphology, structure, and composition of the as-prepared samples were investigated. The temperature-dependent photoluminescence of ZnS:Mn nanorods was analyzed, and the corresponding activation energies were calculated by using a simple two-step rate equation. Mn2+-related orange emission (4T1 → 6A1) demonstrates high stability and is comparatively less affected by the temperature variations than the defect-related emission. A metal–semiconductor–metal junction ultraviolet photodetector based on the nanorod networks has been fabricated by a cost-effective method. The device exhibits visible blindness, superior ultraviolet photodetection with a responsivity of 1.62 A/W, and significantly fast photodetection response with the rise and decay times of 12 and 25 ms, respectively.

Progress in ultraviolet photodetectors based on II–VI group compound semiconductors

“…7h). Furthermore, another MSM junction photodetector based on ZnS:Mn NRs showed the solar-blind superior UV photodetection, and a fast response of 12 ms. 112…”

Direct, simple, rapid, and real‐time monitoring of ultraviolet B level in sunlight using a self‐powered and flexible photodetector

“…Although the charge carriers in such nanoscale ZnS particles can be excited under UVB‐C light, they generally exhibit unsatisfactory charge transport characteristics due to the presence of numerous grain boundaries in the NP film 17 . To overcome this issue, the ZnS‐based UVB‐C detectors reported in previous studies required an applied voltage to artificially motivate the photogenerated electrons in the ZnS region to move toward the electrode 7,18,19 . However, applying an external electric field sacrifices two important aspects of the device: (i) self‐powered operation (no energy consumption), and (ii) low dark current (low leakage current in darkness).…”

“…However, applying an external electric field sacrifices two important aspects of the device: (i) self‐powered operation (no energy consumption), and (ii) low dark current (low leakage current in darkness). For instance, although a device structured with Ag/Mn‐doped ZnS/Ag showed a high current under 310‐nm light (135 μA), a high dark current (130 μA) significantly reduced the on/off current ratio of the device even at low external bias of 0.1 V 19 …”

“…17 To overcome this issue, the ZnS-based UVB-C detectors reported in previous studies required an applied voltage to artificially motivate the photogenerated electrons in the ZnS region to move toward the electrode. 7,18,19 However, applying an external electric field sacrifices two important aspects of the device: (i) self-powered operation (no energy consumption), and (ii) low dark current (low leakage current in darkness). For instance, although a device structured with Ag/Mn-doped ZnS/Ag showed a high current under 310-nm light (135 μA), a high dark current (130 μA) significantly reduced the on/off current ratio of the device even at low external bias of 0.1 V. 19 In this study, we demonstrate a self-powered and wearable ZnS-based UVB-C detector that can be used for the estimation of UVB intensity under sunlight (here, UVC from sunlight is completely absorbed by the ozone layer) in a direct, rapid, precise, and convenient manner.…”

“…7,18,19 However, applying an external electric field sacrifices two important aspects of the device: (i) self-powered operation (no energy consumption), and (ii) low dark current (low leakage current in darkness). For instance, although a device structured with Ag/Mn-doped ZnS/Ag showed a high current under 310-nm light (135 μA), a high dark current (130 μA) significantly reduced the on/off current ratio of the device even at low external bias of 0.1 V. 19 In this study, we demonstrate a self-powered and wearable ZnS-based UVB-C detector that can be used for the estimation of UVB intensity under sunlight (here, UVC from sunlight is completely absorbed by the ozone layer) in a direct, rapid, precise, and convenient manner. We first studied a simple vertically stacked p-n photodiode in an indium tin oxide (ITO)/ZnS NP/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) structure.…”