Highly Sensitive and Tunable Self-Powered UV Photodetectors Driven Jointly by p-n Junction and Ferroelectric Polarization

Abstract

Ferroelectric (FE) materials are thought to be promising materials for self-powered ultraviolet (UV) photodetector applications because of their photovoltaic effects. However, FE-based photodetectors exhibited poor performance because of the weak photovoltaic effect of FE depolarization field (E dp) on the separation of photo-generated carriers. In this work, self-powered photodetectors based on both E dp and built-in electric field at the p-n junction (E p‑n) were designed to obtain enhanced device performance. A NiO/Pb0.95La0.05Zr0.54Ti0.46O3 (PLZT) heterojunction-based device is constructed to take advantage of energy level alignments that favor electron extraction. The device exhibits a tunable performance upon varying the polarization direction of PLZT. The NiO/PLZT heterojunction-based device with the PLZT layer in the poling down state shows a higher responsivity [R = (1.8 ± 0.12) × 10–4 A/W] and detectivity [D* = (3.69 ± 0.2) × 109 Jones], a faster response speed (τr = 0.34 ± 0.03 s, τd = 0.36 ± 0.02 s), and a lower dark current [I dark = (1.3 ± 0.19) × 10–12 A] under zero bias than the PLZT-based device because of the synergistic effects of E dp and E p‑n. Moreover, under weak-light illumination (0.1 mW/cm2), it exhibits even higher R [(6.3 ± 1.2) × 10–4 A/W] and D* [(1.29 ± 0.26) × 1010 Jones] values, which surpass those of most previously reported FE-based self-powered photodetectors. Our work emphasizes the role of the coupling effect between E p‑n and E dp in the photovoltaic process of NiO/PLZT heterojunction-based devices and provides an effective way to promote the self-powered UV photodetector applications.

High‐Performance Self‐Powered Ultraviolet Photodetector based on Coupled Ferroelectric Depolarization Field and Heterojunction Built‐In Potential

“…[14][15][16] For ferroelectric-based self-powered UV photodetectors, the ferroelectric depolarization electric field (E dp ) and the built-in electric field at the ferroelectric/electrode interface are the main driven force of photogenerated carriers. [6,17,18] However, the device performance of so far reported ferroelectric-based self-powered UV photodetectors is yet inferior, owing to the limited photogenerated carriers separation ability of ferroelectric depolarization electric field. [17] For example, responsivities (R) of these detectors are on the order of 10 −7 -10 −4 A W −1 , which are much lower than those of the semiconductor-based detectors.…”

“…[6,17,18] However, the device performance of so far reported ferroelectric-based self-powered UV photodetectors is yet inferior, owing to the limited photogenerated carriers separation ability of ferroelectric depolarization electric field. [17] For example, responsivities (R) of these detectors are on the order of 10 −7 -10 −4 A W −1 , which are much lower than those of the semiconductor-based detectors. [17,[19][20][21][22][23] Thus, it's highly demanding to further optimize the device performance of ferroelectric-based self-powered UV detectors.…”

“…[17] For example, responsivities (R) of these detectors are on the order of 10 −7 -10 −4 A W −1 , which are much lower than those of the semiconductor-based detectors. [17,[19][20][21][22][23] Thus, it's highly demanding to further optimize the device performance of ferroelectric-based self-powered UV detectors. In ferroelectric-based solar cells, the device performance can be effectively improved by combining ferroelectric materials with various semiconductor materials, such as ZnO, [24][25][26] CuO, [27] and NiO, [28] to construct ferroelectricsemiconductor heterojunctions.…”

Self‐Powered and Spectrally Distinctive Nanoporous Ga2O3/GaN Epitaxial Heterojunction UV Photodetectors

“…Several groups recently demonstrated self‐powered heterojunction UV PDs. [ 22–24 ] Chen et al [ 25 ] reported a self‐powered PD based on NiO and a ferroelectric (FE) material (Pb 0.95 La 0.54 Ti 0.46 O 3 ) with a responsivity of 0.18 mA W −1 and a low dark current of 1.3 pA. The device performance enhancement was mainly due to the combined FE depolarization field and the built‐in field.…”

Enhanced Photoresponse in GeSe‐Based Phototransistors by Ferroelectric Gating

“…[24,25] In addition, the high remanent polarization of the ferroelectric gate materials ensures a high gate electric field in such devices even after the removal of the gate voltage. The previously developed ferroelectric-gated photodetectors based on bulk ZnO/BaTiO 3 [26] and NiO/ Pb 0.95 La 0.05 Zr 0.54 Ti 0.46 O 3 [27] heterostructures typically possess low photoresponsivity of the order of 10 À3 A W À1 . The reported ferroelectric-gated photodetectors with 2D channel materials, such as MoS 2 [28] and In 2 Se 3 , [29] engage ferroelectric polymer top gate, which adds complexity in device fabrication.…”