Laser modified ZnO/CdSSe core-shell nanowire arrays for Micro-Steganography and improved photoconduction

One-dimensional nanostructures of II-VI ternary alloys: synthesis, optical properties, and applications

One-dimensional (1D) nanostructures of II-VI ternary alloys are of prime interest due to their compatible features of both 1D nanostructures and semiconducting alloys. These features can facilitate materials with tunable bandgaps, which are crucial to the performance of photoelectrical devices. Herein, we present a comprehensive review summarizing the recent research progress pertinent to the diverse synthesis, optical fundamentals and applications of 1D nanostructures of II-VI ternary alloys. Considering multifunctional applications, the different growth mechanisms of the rational design and synthesis techniques are highlighted. Investigations of the fundamentals of the optical and photoelectrical properties of ternary alloyed II-VI semiconductors via the corresponding characterization techniques are also particularly discussed. Furthermore, we present the versatile potential practical applications of these materials. Finally, we extend the discussion to the most recent research advances on quaternary alloys, which provides a possible prospective forecast for the sustained development of alloyed 1D nanostructures.

Controllable Vapor Growth of Large-Area Aligned CdS x Se1-x Nanowires for Visible Range Integratable Photodetectors

The controllable growth of large area band gap engineered-semiconductor nanowires (NWs) with precise orientation and position is of immense significance in the development of integrated optoelectronic devices. In this study, we have achieved large area in-plane-aligned CdS _x Se_1-x nanowires via chemical vapor deposition method. The orientation and position of the alloyed CdS _x Se_1-x NWs could be controlled well by the graphoepitaxial effect and the patterns of Au catalyst. Microstructure characterizations of these as-grown samples reveal that the aligned CdS _x Se_1-x NWs possess smooth surface and uniform diameter. The aligned CdS _x Se_1-x NWs have strong photoluminescence and high-quality optical waveguide emission covering almost the entire visible wavelength range. Furthermore, photodetectors were constructed based on individual alloyed CdS _x Se_1-x NWs. These devices exhibit high performance and fast response speed with photoresponsivity ~ 670 A W^-1 and photoresponse time ~ 76 ms. Present work provides a straightforward way to realize in-plane aligned bandgap engineering in semiconductor NWs for the development of large area NW arrays, which exhibit promising applications in future optoelectronic integrated circuits.

Morphology and composition of oxidized InAs nanowires studied by combined Raman spectroscopy and transmission electron microscopy

Any device exposed to ambient conditions will be prone to oxidation. This may be of particular importance for semiconductor nanowires because of the high surface-to-volume ratio and only little is known about the consequences of oxidation for these systems. Here, we study the properties of indium arsenide nanowires which were locally oxidized using a focused laser beam. Polarization dependent micro-Raman measurements confirmed the presence of crystalline arsenic, and transmission electron microscopy diffraction showed the presence of indium oxide. The surface dependence of the oxidation was investigated in branched nanowires grown along the [Formula: see text] and [Formula: see text] wurtzite crystal directions exhibiting different surface facets. The oxidation did not occur at the [Formula: see text] direction. The origin of this selectivity is discussed in terms transition state kinetics of the free surfaces of the different crystal families of the facets and numerical simulations of the laser induced heating.

Ultrahigh photoconductivity of bandgap-graded CdSxSe1-x nanowires probed by terahertz spectroscopy

Superiorly high photoconductivity is desirable in optoelectronic materials and devices for information transmission and processing. Achieving high photoconductivity via bandgap engineering in a bandgap-graded semiconductor nanowire has been proposed as a potential strategy. In this work, we report the ultrahigh photoconductivity of bandgap-graded CdSxSe1-x nanowires and its detailed analysis by means of ultrafast optical-pump terahertz-probe (OPTP) spectroscopy. The recombination rates and carrier mobility are quantitatively obtained via investigation of the transient carrier dynamics in the nanowires. By analysis of the terahertz (THz) spectra, we obtain an insight into the bandgap gradient and band alignment to carrier transport along the nanowires. The demonstration of the ultrahigh photoconductivity makes bandgap-graded CdSxSe1-x nanowires a promising candidate as building blocks for nanoscale electronic and photonic devices.