In Situ Fabrication of PdSe₂/GaN Schottky Junction for Polarization-Sensitive Ultraviolet Photodetection with High Dichroic Ratio

Abstract

Polarization-sensitive ultraviolet (UV) photodetection is of great technological importance for both civilian and military applications. Two-dimensional (2D) group-10 transition-metal dichalcogenides (TMDs), especially palladium diselenide (PdSe 2 ), are promising candidates for polarized photodetection due to their lowsymmetric crystal structure. However, the lack of an efficient heterostructure severely restricts their applications in UV-polarized photodetection. Here, we develop a PdSe 2 /GaN Schottky junction by in situ van der Waals growth for highly polarization-sensitive UV photodetection. Owing to the high-quality junction, the device exhibits an appealing UV detection performance in terms of a large responsivity of 249.9 mA/W, a high specific detectivity, and a fast response speed. More importantly, thanks to the puckered structure of the PdSe 2 layer, the device is highly sensitive to polarized UV light with a large dichroic ratio up to 4.5, which is among the highest for 2D TMD material-based UV polarization-sensitive photodetectors. These findings further enable the demonstration of the outstanding polarized UV imaging capability of the Schottky junction, as well as its utility as an optical receiver for secure UV optical communication. Our work offers a strategy to fabricate the PdSe 2 -based heterostructure for highperformance polarization-sensitive UV photodetection.

Rollable Ultraviolet Photodetector Based on ZnAl‐Layered Double Hydroxide/Polyvinylidene Fluoride Membrane

“…bandgap semiconductors, such as SiC, diamond, Ga 2 O 3 , GaN, ZnS, ZnO, or ZnSe, suffer from problems, such as low sensitivity, long response time, nonlinear photocurrent with incident optical power, and a complicated fabrication process. [3][4][5][6] In addition, the fabrication of a flexible or rollable UV photodetector with sufficient durability has not been reported, despite the great significance of sustainable mechanical flexibility for the sensor in wearable sensing systems.…”

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bandgap semiconductors, such as SiC, diamond, Ga 2 O 3 , GaN, ZnS, ZnO, or ZnSe, suffer from problems, such as low sensitivity, long response time, nonlinear photocurrent with incident optical power, and a complicated fabrication process. [3][4][5][6] In addition, the fabrication of a flexible or rollable UV photodetector with sufficient durability has not been reported, despite the great significance of sustainable mechanical flexibility for the sensor in wearable sensing systems.Many studies have been focused on developing efficient, flexible, and highly sensitive UV photodetectors from various nanostructured materials. As an emerging nanomaterial for effective flexible photodetectors, 2D nanomaterials have attracted considerable attention because of their unique properties, such as atomic-scale thickness, lightweight, and flexibility.

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Transparent p-type CuI film based self-powered ultraviolet photodetectors with ultrahigh speed, responsivity and detectivity

“…To better evaluate its performance, Fig. 2e-g show the photocurrent (I ph ), linear dynamic range (LDR), 31 responsivity (R), [32][33][34] and detectivity (D*) 35,36 under different illumination intensities. I ph is the difference between the light current (I light ) and the dark current (I dark ), which is defined as I ph = I light À I dark .…”

A high-performance self-powered photodetector based on WSe2–graphene–MoTe2 van der Waals heterojunctions

“…[9][10][11][12][13][14][15] Photodetectors are one of the key components of multifunctional technology and many devices. [16][17][18] TMDs have strong light-matter interactions and ultra-wide band gaps from visible to infrared. [19][20][21] Therefore, TMDs are the ideal material candidates for photodetector fabrication.…”