Vertically aligned ZnO/CdTe core-shell nanocable arrays-on-indium tin oxide (ITO) are fabricated by electrochemical deposition of CdTe on ZnO nanorod arrays in an electrolyte close to neutral pH. By adjusting the total charge quantity applied during deposition, the CdTe shell thickness can be tuned from several tens to hundreds of nanometers. The CdTe shell, which has a zinc-blende structure, is very dense and uniform both radially and along the axial direction of the nanocables, and forms an intact interface with the wurtzite ZnO nanorod core. The absorption of the CdTe shell above its band gap ( approximately 1.5 eV) and the type II band alignment between the CdTe shell and the ZnO core, respectively, demonstrated by absorption and photoluminescence measurements, make a nanocable array-on-ITO architecture a promising photoelectrode with excellent photovoltaic properties for solar energy applications. A photocurrent density of approximately 5.9 mA/cm(2) has been obtained under visible light illumination of 100 mW cm(-2) with zero bias potential (vs saturated calomel electrode). The neutral electrodeposition method can be generally used for plating CdTe on nanostructures made of different materials, which would be of interest in various applications.

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Large area Ga-doped ZnO nanowire arrays have been vertically grown on transparent conducting substrate by a simple chemical vapor deposition method. Experimental results reveal the well-aligned array morphology and the uniform Ga concentration in these nanowires with individual nanowires of single crystallinity. In particular, direct I−V measurements performed on a single nanowire on indium−tin oxide (ITO) substrate disclose both the low resistivity of nanowire and its Ohmic contact with the conducting substrate, which characteristics make them promising candidates for various optoelectronic and energy applications including photovoltaic cells.

CdTe nanorod arrays on ITO have been demonstrated using a catalyst-free thermal evaporation method. Despite the stacking faults observed in the nanorods, they show intense near band edge emission at ∼1.5 eV with a narrow full width at half-maximum of 79 meV and negligible deep-level emission during the room temperature photoluminescence measurement. The device based on the aligned array-on-ITO configuration demonstrates excellent photoresponse to the visible light, which is ascribed to the large absorption coefficient of the material and also suggests good electronic structure quality of the nanorods.