Gate‐Tunable Photodiodes Based on Mixed‐Dimensional Te/MoTe₂ Van der Waals Heterojunctions

Abstract

tunneling transistor, [9] barristors, [10] flexible electronics, [11,12] and optoelectronic devices. [13] That vertically stacked architecture and atomic thickness are much more efficient for charge separation and transport, making 2D vdW heterostructures prospective building block to construct photodetectors. [4,[13][14][15] Besides all-2D heterojunctions, the dangling-bond-free surfaces of 2D materials also enable vdW interaction with different dimensional materials, forming mixed-dimensional vdW heterostructures. [16] Mixed-dimensional vdW heterostructures allow various selecting freedom of materials and may provide an effective method to compensate the intrinsic weakness of 2D crystals to realize their full potential. [17,18] For example, 1D/2D heterostructures may integrate the respective advantages of the two distinct materials, and therefore, improve device performance and even bring diversity and novelty. In this regard, some intriguing and extraordinary devices have been explored by combing the distinct properties from 1D and 2D materials. Sujay et al. used the natural size of singlewalled carbon nanotubes to prepare molybdenum disulfide (MoS 2 ) transistors with a 1 nm physical gate length, removing the need for any lithography or patterning processes that are challenging at these scale lengths. [1] Pyo et al. reported black phosphorus (BP) nanosheet−zinc oxide (ZnO) nanowire heterojunction application for BP-gated junction field effect transistors with n-ZnO channel for the first time. [19] Zhang et al. realized electrical control of spatial resolution in mixed-dimensional heterostructure photodetectors, combining the asymmetric geometry and the gate-tunable Fermi levels of carbon nanotube, tungsten diselenide (WSe 2 ), and graphene. [20] Researchers have used their experiments [1,2,11,12,[19][20][21][22][23][24][25][26][27][28][29][30][31][32] to verify that it is an essential issue to integrate functional nanomaterials with different dimensions together. The advantages of the mixed-dimensional heterostructures, such as great freedom of choosing materials and synergistic effect, will bring more opportunities to nanodevices.Here, we fabricated mixed-dimensional vdW heterostructure photodiodes composed of 1D Te nanowires and 2D MoTe 2 flakes. Te is a typical p-type narrow bandgap semiconductor (with a bandgap of ≈0.35 eV in bulk and ≈1 eV in monolayer) with a unique helical-chain conformation in its crystal structure. [33][34][35] The narrow bandgap and good air stability make Te has great potential in optoelectronic devices. [36] On the The dangling-bond-free surfaces of 2D materials enable them to possess various degrees of freedom to form heterostructures with non-2D materials. This allows for the combination of the advantages of different dimensional materials to fabricate van der Waals (vdW) heterostructures, thereby improving device performance and even bringing diversity and novelty. Herein, a mixed-dimensional vdW heterostructure photodiode comprising a 1D tellurium (Te) nanowire and a 2D molybd...

Ultrasensitive and Broad‐Spectrum Photodetectors Based on InSe/ReS2 Heterostructure

“…Figure 5c represents the dependence of D * and EQE on different incident light wavelengths at V ds = 8 V and V g = 0 V. It is clear that the detectivity values of photodetectors are more than 10 14 among 365-965 nm spectra, which are higher than the most reported broad-spectrum photodetectors based on 2D materials (see Table S1 in the Supporting Information). [6,10,20,23,42] As shown in Figure 5c (the black line), like the detectivity, the EQE has similar wavelength dependence on the photoresponse spectrum, where the maximum value is 1.52 × 10 6 % at 365 nm incident light wavelength, exceeding most of the reported photodetectors. [43][44][45] Figure 5d shows the NEP as a function of wavelength at V ds = 8 V, demonstrating an ultralow noise equivalent power.…”

“…It is faster than those of the reported heterojunction photodetectors based on photogating effect (see Table S1 in the Supporting Information). [17,22,23,41,42] The photoconductive gain can be obtained, according to the transfer curve (Figure 2b) and the following equations…”

Recent Progress in Anisotropic 2D Semiconductors: From Material Properties to Photoelectric Detection

“…A series of mixed‐dimensional vdW heterostructures optoelectronic devices has been fabricated for next‐generation photodetectors. [ 114–117 ] Polarization sensitivity are most common in the device with a single material and have also been demonstrated in heterojunction of anisotropic 2D material. For the heterojunction broken gap, the photogenerated electrons and holes are separated and extracted more efficiently in the area of the overlap of two materials.…”

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

“…The two junction-type photodetectors separate photocarriers through built-in electric fields and the photoelectrochemical-type photodetectors use energy barriers between the electrode materials and the electrolyte to promote the separation of photogenerated carriers. 27–34 Among them, junction-type self-powered photodetectors have simpler structures and 2D materials are very suitable for building junction-type photodetectors. However, the performance of traditional junction-type self-powered photodetectors is still limited.…”