Synthesis and properties of crystalline InP nanowires with amorphous sheath grown from solid source

The nanowires were synthesized by the vapor-liquid-solid (VLS) mechanism on quartz substrates in a tube furnace, using gold seeds as catalysts. The nanowires were examined by XRD, SEM and HRTEM analysis showing InP nanowires with a single-crystalline core covered by an amorphous sheath with diameters ranging from 40 - 100 nm and lengths of tens of micrometers. Single nanowire devices were fabricated by conventional photolithography techniques, using Ti metallic contacts. I-V curves were obtained under dark conditions and under focused illumination. Aiming the illustration of the samples for optoelectronic devices, photoconductivity measurements were conducted, submitting the samples to repeated dark-light cycles under 1 V bias. The presented delay in photo-response can be caused by the presence of carrier trap states originated from the self-organized growth mechanism or from the crystalline/amorphous interface.