Deep Ultraviolet Copper(I) Thiocyanate (CuSCN) Photodetectors Based on Coplanar Nanogap Electrodes Fabricated via Adhesion Lithography

Abstract

Adhesion lithography (a-Lith) is a versatile fabrication technique used to produce asymmetric coplanar electrodes separated by a <15 nm nanogap. Here, we use a-Lith to fabricate deep ultraviolet (DUV) photodetectors by combining coplanar asymmetric nanogap electrode architectures (Au/Al) with solution-processable wide-band-gap (3.5-3.9 eV) p-type semiconductor copper(I) thiocyanate (CuSCN). Because of the device's unique architecture, the detectors exhibit high responsivity (≈79 A W) and photosensitivity (≈720) when illuminated with a DUV-range (λ = 280 nm) light-emitting diode at 220 μW cm. Interestingly, the photosensitivity of the photodetectors remains fairly high (≈7) even at illuminating intensities down to 0.2 μW cm. The scalability of the a-Lith process combined with the unique properties of CuSCN paves the way to new forms of inexpensive, yet high-performance, photodetectors that can be manufactured on arbitrary substrate materials including plastic.

High Responsivity and Response Speed Single‐Layer Mixed‐Cation Lead Mixed‐Halide Perovskite Photodetectors Based on Nanogap Electrodes Manufactured on Large‐Area Rigid and Flexible Substrates

“…The electrical characteristics of the nanogap photodetectors upon scaling the electrodes width are shown in Figure b. The current scales with the coplanar nanogap electrode width in accordance with previous reports of deep UV photodetectors and polymer light‐emitting devices fabricated via a‐Lith. Interestingly, the photocurrent increases with a higher rate than the dark current, as revealed by the slope of the linear fittings of the dark and photocurrent versus diode width plot depicted in Figure c.…”

UV Photodetectors Based on BiOCl Nanosheet Arrays: The Effects of Morphologies and Electrode Configurations

“…To promote the applications of BiOCl nanomaterials in photoelectric devices, further investigation and modification are required to improve the photoelectric properties of BiOCl nanostructures. There are several strategies to upgrade the photoelectric performance of PDs based on low dimensional nanostructures, including the formation of heterojunctions, optimization of sizes, modification of surfaces, construction of specific morphologies, and the development of novel electrode configurations . The first step for assembling high‐performance BiOCl‐based PDs is to select efficient BiOCl nanostructures with favorable morphologies.…”

“…There are several strategies to upgrade the photoelectric performance of PDs based on low dimensional nanostructures, including the formation of heterojunctions, [24,25] optimization of sizes, [26,27] modification of surfaces, [28][29][30] construction of specific morphologies, [31][32][33] and the development of novel electrode configurations. [34][35][36][37] The first step for assembling high-performance BiOCl-based PDs is to select efficient BiOCl nanostructures with favorable morphologies.2D nanosheet arrays have attracted numerous attention in photoelectric devices owing to their superior photoelectric properties. Their high orientation could provide uniform pathways for efficient charge separation and transfer, which reduces the recombination possibilities of charge carries.…”

Flexible nanogap polymer light-emitting diodes fabricated via adhesion lithography (a-Lith)

“…This was achieved simply by changing the mask design used to pattern the first metal electrode from square to an interdigitated shape with varying pitch size (distance between interdigitated fingers) to allow for diode widths ranging from 1 to 20 cm, while the electrode thickness remained constant at 40 nm. Scaling the diode width has been proven beneficial for both radiofrequency diodes [12], by further enhancing their current driving capabilities, as well as for photodetector applications [16], since it allows significant increase of the photocurrent, whilst retaining the diode's dark current at relatively low levels. Figure 3(a) shows the I-V characteristics of each nanogap PLED device upon increasing the electrodes size.…”