Ferroelectric Localized Field–Enhanced ZnO Nanosheet Ultraviolet Photodetector with High Sensitivity and Low Dark Current

Abstract

Zinc oxide (ZnO) nanosheets have demonstrated outstanding electrical and optical properties, which are well suited for ultraviolet (UV) photodetectors. However, they have a high density of intrinsically unfilled traps, and it is difficult to achieve p-type doping, leading to the poor performance for low light level switching ratio and a high dark current that limit practical applications in UV photodetection. Here, UV photodetectors based on ZnO nanosheets are demonstrated, whose performance is significantly improved by using a ferroelectric localized field. Specifically, the photodetectors have achieved a responsivity of up to 3.8 × 10 A W , a detectivity of 4.4 × 10 Jones, and a photocurrent gain up to 1.24 × 10 . These device figures of merit are far beyond those of traditional ZnO ultraviolet photodetectors. In addition, the devices' initial dark current can be easily restored after continuous photocurrent measurement by using a positive gate voltage pulse. This study establishes a new approach to produce high-sensitivity and low-dark-current ultraviolet photodetectors and presents a crucial step for further practical applications.

A Fully Transparent, Flexible, Sensitive, and Visible‐Blind Ultraviolet Sensor Based on Carbon Nanotube–Graphene Hybrid

“…In order to verify the superiority of graphene as an electrode for CNT-based sensors, we fabricated a CNT UV sensor with Au electrodes as control and examined its photoresponse under UV illumination (Figure 5b). [9] The desorption/adsorption processes of oxygen molecules on the CNTs are relatively slower than electron-hole pair generation and separation shown in conventional UV sensors. In the case of CNT-graphene, the change in the charge density from the CNTs by photodesorption would dominate the total resistance change of the sensor www.advelectronicmat.de since the relatively low contact resistance between CNTs and graphene allows the effective charge transfer with minimal interference.…”

“…[3][4][5] However, Si-based UV sensors, the most established commercial sensors, are unsuitable for use in such applications because of their lack of mechanical flexibility and optical transparency and their need for high operating voltage and a long-pass filter to block low energy photons. [7][8][9][10] 1D and 2D semiconducting materials such as ZnO, TiO 2 , GaTe, and MoS 2 are promising candidates for photodetection because of their direct bandgap at room temperature, transparency in the visible region, and mechanical flexibility. [7][8][9][10] 1D and 2D semiconducting materials such as ZnO, TiO 2 , GaTe, and MoS 2 are promising candidates for photodetection because of their direct bandgap at room temperature, transparency in the visible region, and mechanical flexibility.…”

Switchable Two‐Terminal Transparent Optoelectronic Devices Based on 2D Perovskite

“…On the other hand, the device responds well to UV light in the on-state (Figure 4f). [32] It is known that ZnO/perovskite interface has a rich defect state, which are more likely to form an interface state with the perovskite. [17,31] Therefore, the unpaired electrons will accumulate and when the next UV cycle comes, more electrons-holes pair will be photogenerated, leading to different current level.…”

Plasmon‐Enhanced InGaZnO Ultraviolet Photodetectors Tuned by Ferroelectric HfZrO

“…[18] IGZO has shown great potential in UV optoelectronic applications [19] on account of high mobility, room-temperature fabrication, and good chemical stability. [23][24][25][26][27][28][29][30] Ultrahigh localized electric field introduced by ferroelectric films deplete the background charge carriers of the semiconductor channel which is larger than that depleted by gate bias in traditional field effect transistors. Yet, they suffer from low photoresponsivity (<100 A W -1 or <1 A W -1 ) and high dark current (≈1 nA).…”

“…[23][24][25][26][27][28][29][30] Ultrahigh localized electric field introduced by ferroelectric films deplete the background charge carriers of the semiconductor channel which is larger than that depleted by gate bias in traditional field effect transistors. [23][24][25][26][27][28][29][30] Ultrahigh localized electric field introduced by ferroelectric films deplete the background charge carriers of the semiconductor channel which is larger than that depleted by gate bias in traditional field effect transistors.…”