Efficient Suppression of Charge Recombination in Self-Powered Photodetectors with Band-Aligned Transferred van der Waals Metal Electrodes

Abstract

Recombination of photogenerated electron–hole pairs dominates the photocarrier lifetime and then influences the performance of photodetectors and solar cells. In this work, we report the design and fabrication of band-aligned van der Waals-contacted photodetectors with atomically sharp and flat metal–semiconductor interfaces through transferred metal integration. A unity factor α is achieved, which is essentially independent of the wavelength of the light, from ultraviolet to near-infrared, indicating effective suppression of charge recombination by the device. The short-circuit current (0.16 μA) and open-circuit voltage (0.72 V) of the band-aligned van der Waals-contacted devices are at least 1 order of magnitude greater than those of band-aligned deposited devices and 2 orders of magnitude greater than those of non-band-aligned deposited devices. High responsivity, detectivity, and polarization sensitivity ratio of 283 mA/W, 6.89 × 1012 cm Hz1/2 W–1, and 3.05, respectively, are also obtained for the device at zero bias. Moreover, the efficient suppression of charge recombination in our air-stable self-powered photodetectors also results in a fast response speed and leads to polarization-sensitive performance.

Wafer-Scale 1T′ MoTe2 for Fast Response Self-Powered Wide-Range Photodetectors

“…These results demonstrate that our UHV-fabricated Pd-1T′-MoTe 2 -Au PD device could effectively separate the photocarrier and suppress the recombination. The performance is comparable to the recent work on ReSe 2 with sophisticated transferred metal integration electrodes. , …”

Robust Anti-Ambipolar Behavior and Gate-Tunable Rectifying Effect in van der Waals p–n Junctions

“…The study also shows that the doping density of the p-and nchannels will affect the width of the Gaussian shape of the transfer current. Although the simulation does not show a leakage current at negative V ds bias when V g is over 25 V, it might be due to metal diffusion and the quality of metal− semiconductor interfaces during electrode fabrication, 48,49 where electrons are injected into the p-contact at reverse V ds when the gate bias lowers the potential. We also determined theoretically the transfer characteristic curve of the WSe 2 /SnS 2 heterostructure under 532 nm laser irradiation (Figure 4f).…”

Van Der Waals Metal Contacts for Electronic and Optoelectronic Devices

“…(e) Energy band alignments of the Au/ReSe 2 /Ag photodiode with different metal contact configurations (vdW/deposited) under illumination. Reproduced from ref . Copyright 2021 American Chemical Society.…”

“…The photoswitching response times of the vdW metal-contacted photodetector with the channel length (∼30 μm) were measured to be 332 μs (rise time) and 554 μs (fall time), respectively (Figure 20c). Wu et al 84 reported air-stable self-powered photodetectors by using transferred Ag and Au electrodes. As shown in Figure 20d,e, the lateral-structured Au/ReSe 2 /Au photodetector with the vdW integration demonstrates an ideal asymmetric Schottky barrier height without Fermi-level-pinning.…”