An International Research Journal

AJP Vol 25 No 8

AJP

SSN : 0971 - 3093

Vol 25, No 8, August, 2016

25th Anniversary Year of AJP-2016


Asian Journal of Physics                                                                                                        Vol. 25 No 8, 2016, 977-983


Tailoring thermal conductivity in SnSe by AgSbTe2 addition


Shovit Bhattacharya1*, Mandira Majumder1, 2, Ranu Bhatt1, Sudhindra Rayaprol3, Ranita Basu1, Anil Bohra1, Ajay Singh1 and D K Aswal1

1Technical Physics Division, B.A.R.C., Trombay, Mumbai- 400 085

2Department of Applied Physics, Indian School of Mines, Dhanbad- 826 004

3UGC-DAE CSR, Mumbai Center, R-5 Shed, BARC, Trombay, Mumbai-400 085

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Lead free materials have gained considerable interest in the field of Thermoelectrics due to environmental issues. SnTe is an interesting alternative to the well established PbTe as an efficient thermoelectric material, owing to similar electronic and structural similarity. Conversely, the biggest challenge in SnTe is the intrinsically high carrier concentration due to substantial Sn vacancies, which is extremely unlikely to be overcome by chemical substitutions. In this perspective, composites of (SnTe)1-x(AgSbTe2)x [x = 0, 0.25, 0.5, 0.75 and 1] were prepared in order to tailor its thermal conductivity. In this paper we report the suppression of the thermal conductivity as a function of increasing concentration of AgSbTe2 in the composite. © Anita Publications. All rights reserved.

Keywords: Thermoelectric material, thermal conductivity.

Total Refs: 8

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Asian Journal of Physics                                                                                                        Vol. 25 No 8, 2016, 993-998


 H2S sensing properties of ZnO microcrystals having almond morphology


Savita Dange1*, S N Dange2, N S Ramgir3 and P S More1

1Department of Physics, The Institute of Science, M.C.Road, Fort, Mumbai-400 032, India

2Department of Physics, Jai Hind College, ‘A’ Road , Churchgate, Mumbai-400 020, India

3Technical Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India

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Gas sensing properties of zinc oxide microcrystals having almond like morphology have been investigated towards H2S gas. Uniform thin film of almond like microcrystals of zinc oxide was synthesised by using chemical bath deposition method at room temperature. The almond microcrystals show average tip size of about 100 nm and length of about 1.5 μm. The ZnO film was tested for H2S gas having 50 ppm concentration for temperatures upto 300°C. The film showed highest percentage response at 250°C and fast response and recovery time at 300°C. The structural and optical properties of the ZnO film were characterized by X-ray diffraction (XRD), UV-Vis and Scanning electron microscopy (SEM). © Anita Publications. All rights reserved.

Keywords: Zinc oxide, Almond morphology, Micro crystals, H2S gas sensor, Response time.

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Asian Journal of Physics                                                                                                     Vol. 25 No 8, 2016 1029-1036


A comparative study of the influence of vanadium pentoxide layer

on the ITO surface of organic light emitting diode


D Saikia* and R Sarma**

Thin Film Laboratory, Department of Physics, J. B. College, Jorhat, Assam, India

Pin code: 785001, Telephone: 8011468483, Fax:(0376)2300605

 

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In this paper the influence of vanadium pent oxide (V2O5) layer on the Tin-doped indium oxide (ITO) surface of organic light emitting diode has been reported. Here hole injection is directly affected by the different thicknesses of V2O5films on ITO surface. The ITO/V2O5(15 nm) bilayer anode shows better device performance compared to the bare ITO anode and that of the other thicknesses of V2O5 films. Enhanced device performance is due to the better transmittance property and lower surface resistivity of ITO/V2O5(15nm) bilayer anode combination. In this work N, N’-bis (3- methyl phenyl) - N, N’ (phenyl) -benzidine (TPD) is used as a hole transport layer and Tris (8-hydroxy quinolinato) aluminium (Alq3) as emitting layer. Our results indicate that the ITO/V2O5(15nm) bilayer anode is a better choice to enhanced the hole injection in OLED devices. Here we obtained maximum value of current and power efficiency as 5.6 Cd/A and 2.83 lm/W respectively. © Anita Publications. All rights reserved.

Keywords: Optoelectronics, Vanadium Pent oxide (V2O5), Indium tin oxide (ITO) and Figure of merit (FOM).

Total Refs : 23

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Prospect of molecular clocks
Masatoshi Kajita
National Institute of Information and Communications Technology
Koganei, Tokyo 184-8795, JAPAN
While uncertainties of some of the atomic transition frequencies have been reduced to the level of 10–8, the molecular transition frequencies are currently difficult to be measured with the uncertainty below 10–15. This is mainly because of the complicated energy levels of the molecules having the vibrational-rotational states. This paper lists some molecular transition frequencies, which can be measured with the uncertainties lower than 10–16. © Anita Publications. All rights reserved.

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