Core–shell CdS:Ga–ZnTe:Sb p–n nano-heterojunctions: fabrication and optoelectronic characteristics

Abstract

In this study, we reported on the construction of p-n junction based on crystalline Ga-doped CdS/polycrystalline ZnTe nanostructure (NS) for optoelectronic device application. The coaxial nano-heterojunction was fabricated by a two-step growth method. it is found that absorption edge of CdS:Ga/ZnTe:Sb core-shell NSs red shifted to about 580 nm, compared with CdS nanowires (520 nm). The as-fabricated core-shell p-n junction exhibited obvious rectification characteristics with low turn-on voltage of ~0.25 V. What is more, it showed stable and repeatable photoresponse to 638 nm light illumination, with a responsivity and detectivity of 1.55×10 3 AW -1 and 8.7×10 13 cmHz 1/2 W -1 , respectively, much higher than other photodetectors with similar device configuration.The generality of this study suggests that the present coaxial CdS:Ga/ZnTe:Sb core-shell nano-heterojunction will have great potential applications in future nano-optoelectronic devices.

Heterojunctions Based on II-VI Compound Semiconductor One-Dimensional Nanostructures and Their Optoelectronic Applications

“…Consequently, the plasmonic device exhibits enhanced photocurrent in comparison with a device without Ag nanoparticles. Luo et al constructed CdS-ZnTe core-shell nano-heterojunction photodetectors and measured their photoresponse under light illumination with a wavelength of 638 nm and light intensity of 2 mW cm -2 at 1 V (Figure 14) [25]. The fabricated core-shell nano-heterojunction photodetectors exhibited responsivity of 1.55 × 10 3 AW −1 , conductive gain of 3.3 × 10 3 , detectivity of 8.7 × 10 12 cm Hz 1/2 W −1 , which are much higher than the devices based on is greatly enhanced by the piezo-phototronic effect [34].…”

CdS-Decorated Al-Doped ZnO Nanorod/Polymer Schottky Junction Ultraviolet–Visible Dual-Wavelength Photodetector

“…Ultraviolet–Visible (UV–Vis) dual-wavelength photodetectors are very much attractive for several important applications, like broad wavelength emission detection and environmental and biological research. − Heterojunction made with high and low band gap semiconductors is a common approach for broadband photodetection. − One-dimensional (1D) ZnO nanostructures such as nanowires, nanorods, and novel metal electrodes (Au, Ag, Pt, Ni) contacts have been studied extensively for UV photodetector application due to high band gap of ZnO (∼3.2 eV), superior carrier mobility, simple device geometry, low dark current, fast response and recovery times, and high quantum efficiency. − Several research works have been focused on the improvement of optoelectronic properties of ZnO by doping several metal impurities such as Ga, Al, In, etc. − Al-doped ZnO is particularly important for optoelectronic device applications due to its easy synthesis process, high electrical conductivity, and superior optical properties. − Although doping enhances the carrier mobility and UV absorption, band gap engineering is required for UV–visible photoabsorption of ZnO. Combination of ZnO with other narrow band gap semiconductor (e.g., ZnSe Cu 2 O, CdSe, CdS) has been proven to be feasible for dual-wavelength detection. − Among these materials, CdS has attracted much attention because of excellent visible photoabsorption, similar lattice structures, and type-II band alignment. − …”

Bi-Assisted CdTe/CdS Hierarchical Nanostructure Growth for Photoconductive Applications

“…Therefore, a lot of studies have been devoted to controlling the structural parameters and morphology of NWs [19][20][21][22]. Especially, many researchers fabricated one-dimensional II-VI heterojunctions to develop highperformance photodetectors [23][24][25][26]. However, the precise control of the NWs with complex hierarchical nanostructures is still a challenge.…”