Recent Advances in Amorphous Semiconductors A ... Kumar Singh Department of Physics, Indian Institute of Science, Bangalore 560012, India ABSTRACT Chalcogenide glasses or amorphous

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    Reviews in Advanced Sciences and EngineeringVol. 1, pp. 292301, 2012(www.aspbs.com/rase)

    Recent Advances in AmorphousSemiconductorsA Correlative Study onSe-Based Metallic Chalcogenide AlloysAbhay Kumar Singh

    Department of Physics, Indian Institute of Science, Bangalore 560012, India

    ABSTRACT

    Chalcogenide glasses or amorphous semiconductors are applicable materials in modern optoelectronics.Understanding of thermal, optical, electrical and structural properties in these materials is useful to demon-strate their potential uses. Particularly physical properties of metal containing chalcogenide glasses are gettingmuch attention owing to their interesting features and wide range structural modification. This work presentsa chronologic development in metal containing chalcogenide glasses and a correlation between optical, elec-trical, thermal parameters for recent developed SeZnIn alloys. Specifically, the variation of optical energyband gap (Eg, electrical conductivity (av, crystallization activation energy (Ec and Hruby number (GFA-glassforming ability parameter) with indium atomic percentage of Se98xZn2Inx (0 x 10) chalcogenide glassesis described. Subsequently, the variation of refractive index (n), Eg, av, Ec and Hruby number with averagecoordination number r of under examined systems is also discussed. Minimum and maximum variations inabove physical parameters are obtained at threshold composition (6 at. wt% of In) and corresponding thresholdstructural unit r value.KEYWORDS: Chalcogenides, Optical Properties, Electrical Properties, Thermal Properties, Glass FormingAbility, Average Coordination Number.

    CONTENTS

    1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2921.1. Background of Metallic Chalcogenide Glasses . . . . . . . . 2921.2. Optical Energy Band Gap . . . . . . . . . . . . . . . . . . . . . 2931.3. Refractive Index . . . . . . . . . . . . . . . . . . . . . . . . . . . 2941.4. Electrical Conductivity . . . . . . . . . . . . . . . . . . . . . . . 2941.5. Crystallization Activation Energy . . . . . . . . . . . . . . . . 2941.6. Hurby Parameter . . . . . . . . . . . . . . . . . . . . . . . . . . . 2941.7. Average Coordination Number . . . . . . . . . . . . . . . . . . 295

    2. Materials Preparations . . . . . . . . . . . . . . . . . . . . . . . . . . 2953. Characterizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

    3.1. Optical Characterization . . . . . . . . . . . . . . . . . . . . . . 2953.2. Electrical Characterization . . . . . . . . . . . . . . . . . . . . . 2963.3. Thermal Characterization . . . . . . . . . . . . . . . . . . . . . 296

    4. Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2964.1. Physical Parameters Variations with Alloys Compositions . 2964.2. Physical Parameters Variations with Alloys Average

    Coordination Number r . . . . . . . . . . . . . . . . . . . . . 2975. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2986. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

    Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300References and Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . 300

    Email: abhaysngh@rediffmail.comReceived: 10 January 2012Accepted: 10 April 2012

    1. INTRODUCTION

    1.1. Background of Metallic Chalcogenide Glasses

    Ternary composition of chalcogenide glasses have beenbroadly studied more than three decades. Such chalco-genide compositions can be prepared by introducing asuitable additive element in well known or new binarymatrix. First most extensively studied ternary AsSSesystem demonstrated by Flaschen et al.,1 they show a wideglass-forming region for this composition. This outcomealso revealed the solid solutions can be formed along theline As2 S3As2 Se3 which proved via IR spectra and X-ray analysis by Velinov and his coworkers.2 The Cova-lent Random Network (CRN) and the Chemically OrderedNetwork (CON) models both satisfy the 8-N rule underthe distribution of bond types in a covalent network withmulti elements. As-rich glasses can be formed AsAs,AsSe, and AsS bonds; thus Se-rich glasses have AsSe,AsS, and SeSe bonds and S-rich glasses AsSe, AsS,and SS bonds. The relative weight of each of the aboveunits is expected to be proportionate to the overall com-position of the glass itself.3 Afterword an intensive effortwas made to deduce thermally stable ternary chalcogencompositions by introducing a suitable alloying element

    292 Rev. Adv. Sci. Eng. 2012, Vol. 1, No. 4 2157-9121/2012/1/292/010 doi:10.1166/rase.2012.1018

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    Singh Recent Advances in Amorphous SemiconductorsA Correlative Study on Se-Based Metallic Chalcogenide Alloys

    into binary alloys like; GeSeTe, SiAsTe, AsTeGe,Ge15Te80As5, AsAgSe, As2S3Gex, PdTeI, Pd2SeI3,GeSSb, Ge4Se5Te, SeGeAs, As40xS60Ix, AgTISe2,GexTe10Se90x, Pb08Sn02Te, CuBiS2, GexSyBrz, Li2S-P2S5-B2S3, Ge25Se75xBix, (FexTi1x3Se4, AsSeTe,CuAsSe, AgInTe2, As020Se040Te040, Ge1xSnxSe2,AgAsS, Ga1xGexTe, TeSeI, SeAgBr, SeAgCl,(Se07Te03100xInx, AsSbS, TlGeTe4, Cs2Au2Se3,As25S65Ag10, Cu35As20Te45, Se1xy TexPy , CuTeIetc.439 for various optoelectronics objectives.In the decade Se-based metal containing chalcogenide

    glassy alloys became attractive materials for investiga-tions in optoelectronics and photonics.4050 These materialsexhibited kind of thermal, electrical and optical propertiesduring the performances.5156 Specifically their variablestructural property makes them interesting for investigationowing to that, they extensively studied4050 by the inves-tigators. Predominantly VIIIIII group alloying glasseshave been getting much attention in last a few years causedrastic change in their thermal, optical and electrical prop-erties at threshold composition/- threshold structural unit(or average coordination number) value.To explore the different aspects of such materials sev-

    eral investigators have been reported their work addressesthe various properties; Garrido et al.57 have studied the ionselective application of AgGeSe chalcogenide glasses.Tomova et al.58 have reported the Cu-ion as selectivemembranes based on chalcogenide glasses. Vassilev et al.have reported the Cd(II) and Zn(II) can be used as selec-tive electrodes5960 with chalcogenide glasses. VeroniqueSousa61 has studied the chalcogenide materials can be usedas non-volatile memories. Madhavan et al.62 have exploredthe spectral properties of CoGeTe amorphous thin film.Kim et al. and Tver et al.6364 have demonstrated thethin film from laser ablation and formation of ferromag-netic spinel microcrystals in metal containing chalcogenidealloys. Hyuk Choi et al.65 have demonstrated the applica-tion of Ag doped thin film in programmable metallization

    Abhay Kumar Singh has born 1976 in India, he received the B.Sc. and M.Sc. degreesfrom Chhatrapati Shahu Ji Maharaj University, in 1998, 2000 and Ph.D. degree in physicsfrom Banaras Hindu University, Varanasi, India, in 2009, respectively. He is presently work-ing as a Dr. D. S. Kothari Post-Doctoral Fellow (funded by university grand commissionNew Delhi) in the Department of Physics, Indian Institute of Science Bangalore, India.His current research interest including, chalcogenide photovoltaic solar cell, chalcogen-nanocomposites, chalcogenide metallic/-non-metallic multicomponent alloys preparations andtheir bulk as well as thin films structural, thermal, optical and electrical characterizations.He was successfully introduced the SeZnIn and SeZnTeIn two new series of chalco-genide glasses in 2009, 2010, with Banaras Hindu University, research group. Experimentalfindings on these two series as well as other compositions glasses he has been demonstrated

    in more than 20 technical research papers in reputed international journals. From January 2005 to February 2004, healso worked as a research staff in Notational Metallurgical Laboratory, Jamshedpur, (CSIR Lab), In applied chemistryand corrosion division, under the project on hot dip galvanizing and their metallographic analysis. He has extensiveexperiences with the process of hot dip galvanizing and their thin films structural analysis by using various characterizingtools and material analysis by using metal analyzer.

    cell. Samson et al.66 have demonstrated the Metamate-rial electro-optic switching at nanoscale thickness. Skouget al.67 have studied the effect of structure on thermal con-ductivity of metallic chalcogenide glasses. Silva et al.68

    have studied the temperature dependence thermo-opticalproperties of metallic chalcogenide glasses. Hu et al.69

    have reported the structural, electrical and optical proper-ties of Cu doped chalcogenide glasses. Sharma and Kumarhave demonstrated70 the role of Cu additive on the dielec-tric relaxation of Se75Te25 and Se85Te15 glassy alloys.Gresty et al.71 have demonstrated the structural phase tran-sitions and superconductivity in Fe1+Se057Te043 glass.Selby et al.72 have suggested the new phases in K/Cu/Th/Sglassy systems. Matsushita et al.73 have demonstratedthe new magnetophenomena in Fe047Pb804In1737Se34 sys-tem. Poudeu et al.74 have introduced the new class ofmetallic semiconductors. In order to this Zhou et al.75

    have introduce the promising thermoelectric properties inAgMoSe compounds.Investigations on metallic chalcogenides not limited

    to above described studies. It is still ongoing towardto forward direction to deduce new future prospectiveadvanced amorphous chalcogenide/semico