Single-crystalline CdTe nanowire field effect transistors as nanowire-based photodetector

The electronic and photoconductive characteristics of CdTe nanowire-based field effect transistors were studied systematically. The electrical characterization of a single CdTe nanowire FET verifies p-type behavior. The CdTe NW FETs respond to visible-near infrared (400-800 nm) incident light with a fast, reversible and stable response characterized by a high responsivity (81 A W-1), photoconductive gain (similar to 2.5 x 10(4)%) and reasonable response and decay times (0.7 s and 1 s, respectively). These results substantiate the potential of CdTe nanowire-based photodetectors in optoelectronic applications.open112423sciescopu

Post-growth modification of electrical properties of ZnTe nanowires

ZnTe nanowires, grown by a vapor-liquid-solid technique are p-type and show a very high intrinsic resistivity. Enhancement of the nanowire conductivity was investigated by vacuum annealing, doping and Joule heating. The current-voltage (I-V) characteristics were measured in all cases and electrical parameters such as resistivity, carrier concentration and mobility were computed from the I-V curves. An improvement of five orders of magnitude in the electrical conductivity was seen after thermal annealing and Joule heating, comparable to the enhancement in conductivity obtained by doping. Published by Elsevier B.V.X1167sciescopu

Annealing effect on the thermal conductivity of thermoelectric ZnTe nanowires

We report here the effect of thermal annealing on the thermal conductivity of ZnTe nanowires measured on a microfabricated suspended device. Molecular dynamics simulation was used to calculate the effect of contacts on the measurements at different temperatures and to estimate the intrinsic nanowire thermal conductivity values. A decrease in thermal conductivity was observed after each thermal annealing step at all the measured temperatures. Thermal annealing can be a potential method to improve the thermoelectric efficiency of nanowires, not only by enhancing the electrical conduction as demonstrated before, but also by suppressing the thermal transport at the same time. (C) 2014 Elsevier B.V. All rights reserved.X1122sciescopu

Bandgap engineering of CdxZn1-xTe nanowires

Bandgap engineering of single-crystalline alloy CdxZn1-xTe (0 <= x <= 1) nanowires is achieved successfully through control of growth temperature and a two zone source system in a vapor-liquid-solid process. Extensive characterization using electron microscopy, Raman spectroscopy and photoluminescence shows highly crystalline alloy nanowires with precise tuning of the bandgap. It is well known that bulk CdxZn1-xTe is popular for construction of radiation detectors and availability of a nanowire form of this material would help to improve detection sensitivity and miniaturization. This is a step forward towards the accomplishment of tunable and predetermined bandgap emissions for various applications.open1133sciescopu

Thermal Conductivity of ZnTe Nanowires

The thermal conductivity of individual ZnTe nanowires (NWs) was measured using a suspended micro-bridge device with built-in resistance thermometers. A collection of NWs with different diameters were measured, and strong size-dependent thermal conductivity was observed in these NWs. Compared to bulk ZnTe, NWs with diameters of 280 and 107 nm showed approximately three and ten times reduction in thermal conductivity, respectively. Such a reduction can be attributed to phonon-surface scattering. The contact thermal resistance and the intrinsic thermal conductivities of the nanowires were obtained through a combination of experiments and molecular dynamic simulations. The obtained thermal conductivities agree well with theoretical predictions. (C) 2013 AIP Publishing LLC.open111415sciescopu