Photoconductive Properties of Selenium Nanowire Photodetectors

Abstract

Selenium nanowires with a diameter of about 70 nm and a growth direction along [001] were fabricated via a facile solution method. Photoconductive properties of Se wires were systematically characterized via photodetectors made of single Se nanowire. The photodetectors exhibited a high light on-off current ratio (Ilight/ Idark) of 450, and a fast light response speed of millisecond rise/fall time with excellent stability and reproducibility. It was also observed that the response time strongly depend on the intensity of the illumination light: the rise time and fall time for a typical photodetector is 0.68/1.85, 0.53/1.70, 0.54/1.65, 0.51/1.59, and 0.49/1.58 ms for light intensity of 0.18, 0.26, 0.43, 0.96, and 1.89 mW/cm2, respectively, and the relationship between the light intensity and the photocurrent can be fitted by using a simple power law. The diameters of the nanowire were found to have a significant influence on the response speed with smaller Se nanowires showing higher response speed. Finally, the mechanisms of photoconduction and factors affecting the performance of the photodetectors were elucidated.

Enhanced storage behavior of quasi-solid-state aluminum–selenium battery

“…Meanwhile, the clear lattice fringes with d-spacing of $0.4 nm and 0.5 nm correspond to the (100) and (001) lattice planes of hexagonal phase Se, revealing that the nanowire was single crystalline. [27][28][29] The inset describes a fast Fourier transform (FFT) of the image of Fig. 1(h) which is equivalent to an electron diffraction pattern.…”

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“…Due to the relatively narrow E g of Se nanomaterials, they are capable of displaying strong broadband optical response behaviors. [2,33,34,159] Gates et al used the UV-vis absorption spectra to in-situ characterize the formation of Se nanowires, as shown in Figure 10a. Aliquots of the product were removed from the mixture at a predetermined time and allowed to naturally cool to room temperature.…”

“…As a narrow bandgap semiconductor, Se has a helical chain with weak van der Waals interaction which is considered to have potential applications in high-performance electronic/ optoelectronic devices. [33,59,159,[180][181][182] Ye et al [59] demonstrated that 2D Se nanosheets prepared by vacuum vapor deposition, exhibited excellent p-type transport behaviors with an onstate current density ≈20 mA mm −1 at V ds = 3 V with a high on/off ratio of ≈10 6 . Besides, both the photocurrent (I ph ) and responsivity (R λ ) are linearly proportional to the laser power, indicating that I ph is mainly determined by the photoexcited carriers (Figure 13a,b).…”

A Perspective on Nanowire Photodetectors: Current Status, Future Challenges, and Opportunities

“…Zhai et al [174] pursued a similar thermal evaporation method but with Au nanoparticle catalyst. Others include InP NW PDs [136], NWs of CdTe [175], ultraviolet PDs based on single GaN nanorod p-n junctions [176], InAs/InAsP NWs [177], aligned assemblies of core-shell CdSe/CdS nanorods [178], Ge NW with CdS nanoparticle heterojunction [179], single InP NW devices with back-to-back Schottky barriers [180], Se NWs [181], Ge NW PDs [182], [183], InSb-NW-array PDs [184], CdZnS NW networks [185], metal-semiconductor-metal PDs made from an individual CdS NW [186], Ge NW Schottky PDs [79], [187], Bi 2 S 3 NWs [188], 3-D-to-3-D-transferred Si photoconductor [135], and InP NWs [189].…”