One-Step Preparation of Coaxial CdS-ZnS and Cd1-xZnxS-ZnS Nanowires

Abstract

Preparation of coaxial (core–shell) CdS–ZnS and Cd1–xZnxS–ZnS nanowires has been achieved via a one‐step metal–organic chemical vapor deposition (MOCVD) process with co‐fed single‐source precursors of CdS and ZnS. Single‐source precursors of CdS and ZnS of sufficient reactivity difference were prepared and paired up to form coaxial nanostructures in a one‐step process. The sequential growth of ZnS on CdS nanowires was also conducted to demonstrate the necessity and advantages of the precursor co‐feeding practice for the formation of well‐defined coaxial nanostructures. The coaxial nanostructure was characterized and confirmed by high‐resolution transmission electron microscopy and corresponding energy dispersive X‐ray spectrometry analyses. The photoluminescence efficiencies of the resulting coaxial CdS–ZnS and Cd1–xZnxS–ZnS nanowires were significantly enhanced compared to those of the plain CdS and plain Cd1–xZnxS nanowires, respectively, owing to the effective passivation of the surface electronic states of the core materials by the ZnS shell.

Studies on growth and characterization of ternary CdS1−xSex alloy thin films deposited by chemical bath deposition technique

“…However, for some opto-electronic applications it is important to be able to tune the emission wavelength. The tunability can be achieved through composition modulation, for example, alloyed II-VI semiconductor ternary of CdS 1Àx Se x , Zn x Mg 1Àx O, and Cd 1Àx Mn x S with continuously tuned band gap have been reported [4][5][6][7][8]. Consequently, wavelength tunable emission can be achieved from ternary compounds by simple adjustment of composition.…”

Electronic structure and optical properties of CdSxSe1−x solid solution nanostructures from X-ray absorption near edge structure, X-ray excited optical luminescence, and density functional theory investigations

“…One goal is to have the ability to control the composition of semiconductor alloys and effectively tune the band-gap of a material for a specific function. As a result, various ternary alloys have recently attracted a great deal of attention for their ability to achieve a wide range of band-gaps, [1][2][3][4][5][6][7][8][9][10][11][12] Additionally, nano-materials, such as nano-wires and nano-ribbons, offer greater versatility by providing a wider range of alloy composition and band-gap modulation which is unachievable using traditional epitaxial film materials due to lattice strain at the substrate interface. 13 Ternary chalcogenide semiconductors, particularly cadmium sulpho-selenide (CdS x Se 1Àx ) alloys, have been intensely studied 8,[14][15][16][17][18][19] in part due to the remarkably broad range of stable stoichiometries that can be attained, owing to the small lattice mismatch among the constituent anions.…”

Alternating the Output of a CdS Nanowire Nanogenerator by a White‐Light‐Stimulated Optoelectronic Effect

“…Recently, ZnO-nanowire (NW)-array-based piezoelectric nanogenerators have been demonstrated to convert mechanical energy to electricity by utilizing the coupling effect of the semiconducting and piezoelectric properties of ZnO. [4][5][6] Further exploration of this piezotronic concept [7] has led to the development of a wide variety of ZnO-NW-based piezotronic devices, such as piezoelectric field effect transistors, [8] nanoforce sensors, [8] and gate diodes.[9]More recently, CdS NWs were also successfully demonstrated for piezoelectric nanogenerators.[10] As another member in the wurtzite family, CdS is a piezoelectric, semiconducting, [11] and optoelectric [12] material with a direct energy band gap of about 2.5 eV [13] (corresponding to an on-set absorption of 500 nm). A wide range of 1D CdS nanostructures such as NWs, [14] NW arrays, [15] nanobelts, [16] nanotubes, [17] nanocombs, [18] and tetrapods, [19] have been synthesized by wet-chemistry or vapor-phase processes.…”