Single CdS Nanorod for High Responsivity UV–Visible Photodetector

Abstract

light absorption, [3] as well as the unique optoelectronic properties. [4][5][6][7] Therefore, many researchers are devoted to synthesize various of 1D nanostructures with controllable size, morphology, orientation, and crystallinity. Until now, various 1D nonostructures including nanorods (NRs), nanowires, nanotubes, and nanobelts [4,5,8,9] have been synthesized by many approaches such as chemical vapor deposition (CVD), focused ion beam, vapor-liquid-solid and chemical solutions. [10][11][12][13] Among 1D nanomaterials, 1D nanostructured semiconductor exhibited extensive application in light-emitting diode, transistors, lasers, solar cells, panel displays, field emitters, and photodetector devices. [4,12,14,15] As one of the most important optoelectronic devices, photodetectors can be used to convert the optical signal into electrical signal. Generally, the photodetectors based on 1D nanostructures show high sensitivity, large photocurrent gain, good reliability, and fast response time. [11,16,17] As we know, various 1D semiconductor nanomaterials have been used to fabricate photodetectors such as CdS, ZnO, ZnS, SnO 2 , WS 2 , CdTe, ZnTe, and In 2 Te 3 . [4,[18][19][20][21][22] It has been concluded that the photoresponse properties of these fabricated detectors are determined critically by a variety of parameters including selected materials, contact type of device, as well as the crystalline quality and dimension.As a significant II-VI chalcogenide semiconductor, wurtzite CdS is a direct bandgap semiconductor with the band energy of 2.42 eV at room temperature. [23] The particular characteristics of CdS such as excellent photoconductivity, good chemical stability, low work function (4.2 eV), and the working in visible spectrum, [24] make CdS become a promising candidate in photodetectors. [25] In recent years, many efforts have been used to improve the performance of the CdS photodetector with the novel type of device structure such as side-gated field-effect transistor. [26,27] While, in the area of the traditional Ohmic contact based photodetectors, many efforts still have been dedicated to improve the quantum efficiency, photoresponse ratio, sensitivity, and response time of 1D CdS nanowires photodetectors. [28][29][30] However, less attention has been paid to improve the responsivity of CdS nanwires photodetector despite it is the important parameter to evaluate the device performance such as the ability of the photoelectric conversion.1D nanoscale photodetectors have been extensively investigated for the unique geometry structure and novel physical and chemical properties. The 1D CdS materials have received much attention in the field due to its high photosensitivity and fast response, while how to achieve high responsivity is still in development, despite it is the crucial target to the excellent photo detector. Single crystal CdS nanorods (NRs) are synthesized on SiO 2 /Si substrate over large scale via the chemical vapor deposition method. The individual single CdS nanorod photodetector have been fabr...

Topological structures of transition metal dichalcogenides: A review on fabrication, effects, applications, and potential

“…Complementary to gapless materials such as graphene, 2D TMDs have numerous exceptional properties, such as a direct bandgap, strong spin‐orbit coupling, and excellent electronic and optical properties resulting from quantum confinement 1‐13 . This increases the potential for furthering the basic understanding of TMDs and for their use in cutting‐edge applications in electronics, 14‐20 spintronics, 21‐26 optoelectronics, 27‐32 and energy harvesting, 33‐38 among others. The preparation of 2D TMDs determines the purpose of the material.…”

Recent advances in low‐dimensional semiconductor nanomaterials and their applications in high‐performance photodetectors

“…In addition, MoO 3 nanobelts (NBs) and SnO 2 NBs are the same wide‐bandgap 1D semiconductors, and have been studied in the field of light detection . Among the II‐VI compounds, sulfide semiconductors are also an important part …”

“…[108][109][110][111] Among the II-VI compounds, sulfide semiconductors are also an important part. 65,[112][113][114][115] V-VI semiconductor nanowire is another type of 1D material, which is widely used in the field of optoelectronics such as PDs. 68,[116][117][118][119][120][121][122] Photoelectric devices prepared based on Bi 2 S 3 NWs, Sb-Bi-Se NWs, Sb 2 Se 3 NWs, and so on, all exhibited excellent characteristics; for example, the high spectrum responsivity of Sb-Bi-Se NWs 116 and the ultra-fast response time of Bi 2 S 3 NWs.…”

Boosting Enhancement of the Electron–Phonon Coupling in Mixed Dimensional CdS/Graphene van der Waals Heterojunction

“…[30] Pan et al reported an intensity ratio I 2LO /I 1LO of ≈0.22 for the bulk CdS, [31] while Zhao et al, reported a much higher intensity ratio of 1.97 for 1D CdS nanorods. [23] Also in comblike CdS branched nanostructures, due to the existence of trunk-branch junctions, the intensity ratio of I 2LO /I 1LO at the junctions reaches 1.90, which is higher than that at the trunk and branch parts. [32] Additionally, few layer graphene has a huge amount of free electrons due to the overlapping of the conduction and valence bands.…”