Polarization Sensitive Solar‐Blind Ultraviolet Photodetectors Based on Ultrawide Bandgap KNb₃O₈ Nanobelt with Fringe‐Like Atomic Lattice

Abstract

Low-dimensional ultrawide bandgap semiconductors demonstrate great potential in fabricating solar-blind ultraviolet photodetectors. However, the widespread use of detectors is still limited by the low responsivity, large noise, and dark current, and especially few detectors can fulfill the solarblind ultraviolet detection and the polarization dependence simultaneously. Herein, a polarization sensitive solar-blind ultraviolet photodetector based on ultrathin KNb 3 O 8 nanobelts synthesized via chemical vapor deposition growth, is reported. By selecting suitable substrate and tuning the growth temperature, the nonlayered KNb 3 O 8 crystal is grown into the quasi-1D ultrathin nanobelt with thickness in the range of 4.8-120 nm. Density functional theory calculations and experimental results indicate that the ultrathin KNb 3 O 8 nanobelt possesses an ultrawide bandgap (4.15 eV) as well as unusual in-plane structural anisotropy. Benefiting from the above features, the ultrathin KNb 3 O 8 nanobelt-based device exhibits superior photodetection performances with high responsivity (30 A W −1 ), high detectivity (5.95 × 10 11 Jones), and ultralow dark current (7.1 × 10 −15 A) in the solar-blind ultraviolet region (230-280 nm). In addition, the KNb 3 O 8 photodetector displays strong polarization sensitive photoresponse with a linear dichroic ratio of 1.62 at 254 nm. With these remarkable features, the ultrathin KNb 3 O 8 nanobelt provides great opportunities for designing the next-generation multifunctional solar-blind ultraviolet optoelectronic devices.

Near-Infrared Polarimetric Image Sensors Based on Ordered Sulfur-Passivation GaSb Nanowire Arrays

“…Figure c is the summary of dichroic ratios of single S-GaSb NW, ordered S-GaSb NW array polarization photodetectors in this work, and other reported 1D or quasi-1D polarization photodetectors in previous reports. Both single S-GaSb NW and ordered S-GaSb NWs arrays possess better polarization-sensitive performances than the majority of reported KNb 3 O 8 , SbI 3 , ZrS 3 , Sn II Sn IV S 3 , Sb 2 Se 3 , Nb 1– x Ti x S 3 , Sb 2 S 3 , etc. The obtained data are exhibited in Table S4.…”

A solution-fabricated tellurium/silicon mixed-dimensional van der Waals heterojunction for self-powered photodetectors

“…5(c). And the data can be well fitted by the following function: 61 I ds = I max cos 2 ( θ ) + I min sin 2 ( θ )where θ is the rotation angle between the polarization direction of laser and a -axis of Te nanosheets, and I max and I min are the maximum and minimum fitting photocurrent, respectively. Note that the device shows a decent photocurrent anisotropic ratio ( I max / I min ) of 2.1 under 635 nm light illumination, stemming from the strong in-plane anisotropic photoresponse of Te nanosheets and the effective built-in electric field.…”

Polarity-Reversible Te/WSe2 van der Waals Heterodiode for a Logic Rectifier and Polarized Short-Wave Infrared Photodetector

“…At the optimal V g of −35 V and low power density of 100.5 mW cm –2 , the responsivity ( R ) reaches 5.2 A W –1 ( V ds = −0.8 V), with an external quantum efficiency (EQE) of 420% and calculated specific detectivity ( D ) of 6.8 × 10 9 Jones, as shown in Figure e (details in Figure S12 and Note S1 of the Supporting Information). A shift in the transistor threshold voltage could be observed from the upper part of Figure d, indicating that both photoconductive and photogating effects contribute to photocurrent generation . Particularly, the peak R reaches 1.9 × 10 3 A W –1 for near-infrared 980 nm, corresponding to a calculated D of 2.8 × 10 12 Jones (Figure S13 of the Supporting Information), among the highest reported in Te-based photodetectors. ,− Figure f presents partial time-resolved response curves under 980 nm with a switching frequency of 0.1 and 0.2 Hz for ∼280 continuous cycles, revealing a steady photoresponse characteristic.…”

“…A shift in the transistor threshold voltage could be observed from the upper part of Figure 7d, indicating that both photoconductive and photogating effects contribute to photocurrent generation. 47 Particularly, the peak R reaches 1.9 × 10 3 A W −1 for near-infrared 980 nm, corresponding to a calculated D of 2.8 × 10 12 Jones (Figure S13 of the Supporting Information), among the highest reported in Te-based photodetectors. 26,48−51 The intrinsic anisotropic crystal structure of Te offers enticing possibilities for probing the polarization information on infrared light.…”