Engineering topics

Aswal, D. K.

Publications and source records attributed to Aswal, D. K..

5 records

DOE OSTI2016

Chemical synthesis and characterization of PdTe-Ag{sub 2}Te nanowires heterostructure

Ag{sub 2}Te and Pd doped Ag{sub 2}Te nanowires are synthesized using chemical route. Field Emission Scanning Electron Microscopy (FESEM) shows the presence of nanowires of nearly few micron length and ~ 200 nm diameter. The composition analysis performed using Electron Dispersive Spectroscopy (EDS) shows the presence of almost 1.98 at% palladium. Reitveld refinement of X-ray diffraction (XRD) shows the presence of 0.3 % of PdTe phase in addition to Ag{sub 2}Te in Pd doped Ag{sub 2}Te sample.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

DOE OSTI2016

Attempts to improve the H{sub 2}S sensitivity of TiO{sub 2} films

We report the pulsed laser deposited titanium oxide thin film for H{sub 2}S gas sensing. The surface and bulk electronic structure is revealed using XPS technique. These TiO{sub 2} films showed very good selectivity to H{sub 2}S with response of around ~ 60% at 200°C operating temperature. In order to improve the sensor response so as to realize the technological application, we hereby attempted bi-directional efforts as (i) Nb-doping and (ii) defects engineering in the TiO{sub 2} film. It is revealed that Nb-doping reduces response however defect engineering improves the same.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2016

Improvement in thermoelectric power factor of mechanically alloyed p-type SiGe by incorporation of TiB{sub 2}

Nearly 60% of the world’s useful energy is wasted as heat and recovering a fraction of this waste heat by converting it as useful electrical power is an important area of research{sup [1]}. Thermoelectric power generators (TEG) are solid state devices which converts heat into electricity. TEG consists of n and p-type thermoelements connected electrically in series and thermally in parallel{sup [2]}. Silicon germanium (SiGe) alloy is one of the conventional high temperature thermoelectric materials and is being used in radio-isotopes based thermoelectric power generators for deep space exploration programs.Temperature (T) dependence of thermoelectric (TE) properties of p-type SiGe and p-type SiGe-x wt.%TiB{sub 2} (x=6,8,10%) nanocomposite materials has been studied with in the temperature range of 300 K to 1100 K. It is observed that there is an improvement in the power factor (α{sup 2}/ρ) of SiGe alloy on addition of TiB{sub 2} upto 8 wt.% that is mainly due to increase in the Seebeck coefficient (α) and electrical conductivity (σ) of the alloy.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2016

Study of thermal stability of Cu{sub 2}Se thermoelectric material

Sustainability of thermoelectric parameter in operating temperature range is a key consideration factor for fabricating thermoelectric generator or cooler. In present work, we have studied the stability of thermoelectric parameter of Cu{sub 2}Se within the temperature range of 50-800°C. Temperature dependent Seebeck coefficients and electrical resistivity measurement are performed under three continuous thermal cycles. X-ray diffraction pattern shows the presence of mixed cubic-monoclinic Cu{sub 2}Se phase in bare pellet which transforms to pure α-Cu{sub 2}Se phase with repeating thermal cycle. Significant enhancement in Seebeck coefficient and electrical resistivity is observed which may be attributed to (i) Se loss observed in EDS and (ii) the phase transformation from mixed cubic-monoclinic structure to pure monoclinic α-Cu{sub 2}Se phase.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

WO{sub 3} thin film based multiple sensor array for electronic nose application

Multiple sensor array comprising 16 x 2 sensing elements were realized using RF sputtered WO{sub 3} thin films. The sensor films were modified with a thin layer of sensitizers namely Au, Ni, Cu, Al, Pd, Ti, Pt. The resulting sensor array were tested for their response towards different gases namely H{sub 2}S, NH{sub 3}, NO and C{sub 2}H{sub 5}OH. The sensor response values measured from the response curves indicates that the sensor array generates a unique signature pattern (bar chart) for the gases. The sensor response values can be used to get both qualitative and quantitative information about the gas.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗