Want et al. fabricated the ZnO/Si nanowire arrays by a solution etching/growth method and applied them in photodetectors [15]. The specimen presented a high photodetection sensitivity with an on/off ratio larger than 250 and a peak photoresponsivity of 12.8 mA/W at 900 nm. They also used them in photoelectrochemical cells and found that the 3D nanowire heterostructures demonstrated large enhancement in photocathodic current density (an achieved value as high as 8 mA/cm2) and overall hydrogen evolution kinetics

[16]. Kim synthesized the ZnO/Si nanowire arrays by combining nanosphere AZD6094 molecular weight lithography and solution process [9]. The sample was used in solar cells and exhibited an enhanced photovoltaic efficiency by more than 25% and an improved short circuit current by over 45% compared to the planar solar cells. Nevertheless, all the above reports are chiefly concentrating on the specimen’s performance either on photocatalysis CFTRinh-172 research buy or on optoelectronics. The basic issues, the growth mechanism and the role of key growth parameters on the hierarchical structure formation, are actually neglected.

Since the function of the ZnO/Si nanowire arrays primarily depends on the composition distribution and nanostructure feature, a systematic research about the influence of different growth parameters on the hierarchical nanostructure formation is crucial to the controllable synthesis as well as the related applications. With the above considerations, in this letter, we proposed a rational routine for creating branched ZnO/Si nanowire arrays with hierarchical structure. The specimens were synthesized through growth of crystalline Si nanowire arrays as backbones first, subsequent deposition of ZnO thin film as a seed Idelalisib clinical trial layer on the surface of the backbones, and final hydrothermal growth of ZnO nanowire branches. The successful synthesis of ZnO/Si heterogeneous nanostructures was confirmed by the results of scanning electron

microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), photoluminescence (PL), and reflectance spectra. The experimental parameters, such as the solution type, the substrate direction, and the seed layer, were systematically investigated to determine the optimum growth conditions of the ZnO/Si hierarchical nanostructures. Methods Materials and reagents P-type, boron-doped (100) Si wafers with a resistivity of 1 to 10 Ω cm and a thickness of 450 μm were purchased from BIBW2992 solubility dmso Shanghai Guangwei Electronic Materials Co. Ltd (Shanghai, China). Hydrogen peroxide (H2O2) 30%, nitric acid (HNO3) 65%, sulfuric acid (H2SO4) 95%, hydrochloric acid (HCl) 36%, hydrofluoric acid (HF) 40%, toluene (C6H5CH3), acetone (C3H6O), ethanol (C2H5OH), zinc acetate dihydrate (Zn(CH3COO)2 · 2H2O), and hexamethylenetetramin (C6H12N4) were all bought from Xilong Chemical Co. Ltd (Guangdong, China).