You are here: Home Events Quantum Research Group talk by Dr Aline Simo:

Quantum Research Group talk by Dr Aline Simo:

When Apr 24, 2014
from 12:20 PM to 01:20 PM
Where NITheP Seminar Room, 3rd Level, H-Block
Add event to calendar vCal
iCal

P { margin-bottom: 0.08in; }

QUANTUM RESEARCH GROUP

 

Invites you to a talk by

 

DR ALINE SIMO

 

from: iThemba Labs, Materials Research Department,

Nanosciences Laboratories

 

entitled

 

PHYSICAL PROPERTIES OF VANADIUM DIOXIDE NANOPARTICLES :

Application as 1-D Nanobelts room temperature for hydrogen gas sensing

 

Date: Thursday, 24th APRIL 2014 @ 12h20

 

Venue: NITheP Seminar Room, 3rd Level, H-Block,

 

 

ABSTRACT

 

Transition metal oxides magneli phases present crystallographic shear structure which is of great interest in multiple applications because of their wide range of valence, which is exhibited by the transition metals. The latter affect chemical and physical properties of the oxides. Amongst them we have nanostructures VO2 system of V and O components which are studied including chemical and physical reactions based on non-equilibrium thermodynamics. Due to their structural classes of corundum, rocksalt, wurtzite, spinel, perovskite, rutile, and layer structure, these oxides are generally used as catalytic materials which are prepared by common methods under mild conditions presenting distortion or defects in the case of VO2. Existence of an intermediate phase is proved using an x-ray thermodiffraction experiment providing structural information as the nanoparticles are heated. Potential application as gas sensing device has been the first time obtained due to the high surface to volume ratio, and good crystallinity, purity of the material and presence of suitable nucleating defects sites due to its n-type semiconductor behavior. The I-V behavior obtained in the single nanograin VO2 describes the charge carrier originating from the soliton tunneling conductivity of the material with abrupt jump current correlated to the abrupt Mott insulator without structural phase transition. This was observed by inducing internal holes charges of about 0.018% in the holes levels into conduction band with a source drain field or gate field which make possible the semi-conductor to be used as high frequency oscillator (microwave).

In addition, annealing effect on nanostructures VO2 nanobelts shows a preferential gas reductant of Ar comparing to the N2 gas. Also, the hysteresis loop shows that there is strong size dependence to annealing treatment on our samples. This is of great interest in the need of obtaining high stable and durable material for Mott insulator transistor and Gas sensor device at room temperature.

« May 2017 »
May
SuMoTuWeThFrSa
123456
78910111213
14151617181920
21222324252627
28293031