In‐plane Epitaxy of Bi₂S₃ Nanowire Arrays for Ultrasensitive NIR Photodetectors

Abstract

Semiconductor nanowires (NWs) are considered the ideal building blocks for future nanodevices. [1] In particular, because of their 1D geometry, NWs have attracted tremendous attention due to their potential applications in waveguides, [2] nanolasers, [3] photodetectors (PDs), [4] and field-effect transistors. [5] Although great progress has been made in the synthesis of semiconductor NWs, most of the reported wires were grown with random orientations, which restrained their application in high-density integrated circuits. [6] Generally, practical utilization at the circuit level requires the large-area horizontal alignment of semiconductor NWs with a controlled orientation on a substrate. Several techniques, such as optical tweezers, [7] micromanipulation, [8] and Langmuir-Blodgett assembly [9] may align NWs in well-organized arrays. However, these postgrowth assembly strategies are still subject to poor controllability, low throughput, and high cost, which prevents their application in scale production. [3a,10] The direct epitaxy of semiconductor NWs on an appropriate substrate has great potential to efficiently produce macroscopic-scale wire arrays with horizontal alignment through combining the growth and assembly of NWs into one step. The guided growth of laterally aligned NWs has been successfully achieved for InP NWs on germanium, [11] GaAs NWs on GaAs (100) substrates, [12] GaN and ZnSe NWs on sapphire, [10a,13] etc. These covalent hetero-or homoepitaxies strictly require the substrates and the corresponding epitaxial NWs to have similar crystalline symmetries, lattice parameters, and thermal expansion coefficients to avoid large interface strain. Moreover, the chemical covalent bonds formed between epitaxial NWs and substrates make wire arrays difficult to be peeled off from the grown substrates. This prevents the wires from further being transferred onto other substrates for various functional device applications. Mica, a typical layer-structured mineral, can act as an ideal deposition substrate interacting with the epitaxial wires by the van der Waals (vdW) force, due to its danglingbond-free and atomically smooth surface. [14] The weak vdW force dominated incommensurate epitaxy of wires horizontally on vdW substrates may tolerate a large lattice mismatch, while the wires may still maintain a definite in-plane direction relative to the substrate to minimize the system energy. [15] In addition, the weak interacting force between the epitaxial wire and mica facilitates the transfer of the grown wire arrays without any corrosive reagents etching the substrate, but with the assistance of water. [16] Although mica has been extensively used as a vdW epitaxial substrate for the growth of vertically aligned semiconductor wires and 2D materials, [16,17] the growth of horizontally aligned semiconductor wires on mica is only limited to the material systems of WO 3 , Pb 1Àx Sn x Se, and all inorganic perovskites. [18]

High‐Quality CsAg2I3Microwires Grown by Spatial Confinement Method for Self‐Powered UV Photodetectors

“…The results also show that CsAg 2 I 3 MWs can be grown on a variety of substrates via the spatial confinement method, which is different from the traditional epitaxial growth and beneficial for multifunctional optoelectronic applications. [56][57][58][59] The morphology and chemical component of the prepared CsAg 2 I 3 MWs were characterized by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) elemental mapping. Figure 2a-d shows the SEM images of different width CsAg 2 I 3 MWs grown on the glass substrate, where the width of CsAg 2 I 3 MWs can be adjusted within a certain range from 890 nm to 52 μm by varying the MW growth time.…”

Epitaxial Growth of 2D Bi2O2Se Nanoplates/1D CsPbBr3 Nanowires Mixed‐Dimensional Heterostructures with Enhanced Optoelectronic Properties

“…The wavelength‐dependent photocurrent was measured by a home‐made system constructed with a Lock in amplifier (SR830, Stanford Research Systems, Inc.), grating spectrometer (Zolix, Omni‐λ 500), and xeon lamp (Beijing Changtuo, CHF‐XM‐500 W). [ 11 ] The I – V plot of the device in the dark and illumination was checked by a semiconductor parameter analyzer (Agilent, B4155C). The photoresponse speed of the device was checked by an oscilloscope.…”

“…[ 10 ] The direct epitaxy of semiconductor wires on 2D materials shows the prospect for realizing large‐scale 2D/1D heterostructures with the definite direction alignment of the epitaxial wires relative to the 2D substrate dictated by the epitaxial orientation due to the system energy minimization. [ 11 ] Li et al. firstly reported the one‐step growth of Bi 2 S 3 nanowires on MoS 2 monolayers through defect‐induced co‐nucleus growth, which was applied in field‐effect transistors and photodetectors.…”

Centimeter‐Scale Growth of Unidirectional CsCu2I3 Wire Arrays for High Performance UV Photodetectors

“…Therefore, the surface energy of (001) is higher than that of surfaces (such as (100) and (010) planes) without dangling bonds, which is favorable for growing the wire along c ‐axis (schematically shown in Figure 2k). [ 15,27,28 ] All of these results demonstrate the high crystalline quality of the CsCu 2 I 3 MWs prepared by the MASC method.…”