Growth of multi-step shaped CdTe nanowires and a distinct photoelectric response in a single nanowire

Multi-step shaped CdTe nanowires with a zinc blende phase have been synthesized from the reaction of CdCl2 with diphenyl ditelluride in oleylamine with the assistance of tris(2-ethylhexyl) phosphate (TEHP) at 240 °C for 1 h. The one-dimensional CdTe nanostructured nanowires are observed with lengths up to 20 μm and about 250–300 nm in diameter. Investigations show that TEHP plays an important role in the growth of the nanowires with rough surfaces. The growth process of the nanowires is studied and it is found that the growth of the multi-step nanowires results from the spontaneous aggregation and assembly of small-sized flying saucer-like nanostructures along the axial direction under an oriented attachment growth regime with the assistance of TEHP. Meanwhile, the electrical and photoelectrical properties of the as-prepared CdTe nanowires are investigated and the nanowires exhibit p-type electrical characteristics. More importantly, a distinct strong photoelectric response is observed in a typical individual nanowire at room temperature since the photocurrent is over 60 times that of dark current at white light illumination.