Bi2Se3 bulk alloys were synthesized using a standard mono-temperature melting process and used as source materials to deposit thin films on non-conductive super cleaned glass substrates by a vacuum thermal evaporation technique. Both bulk and thin-film samples were polycrystalline as confirmed by X-ray diffraction patterns. The film samples were subjected to the annealing process in air atmosphere at 250 and ... Read more

PolycrystallinebulksamplesofBi2(Se1−xTex)3systemwithx=0.0–0.9werepreparedbythe conventionalmeltingmethod.Successfullyandcheaply,SeatomswerereplacedbyTeatomstoget Bi2Se3-Bi2Te3orevenBi2Te3alone.DifferenceofmassandsizebetweenTeandSeatomsisexpected toresultininterestingpropertiesintheBi2(Se1−xTex)3system.Allcompoundsshowedametalsemiconductorconductivitytransition.TheelectricalconductioninthepristineBi2Se3compound increaseswiththelowTedopingratio(x=0.3)thendecreasesmonotonicallyforfurtheramountsof Te.TheSeebeckcoefficientofBi2Se3compoundispositiveshowingupap-typeconduction.However, introducingTecontentincreasesthen-typeconductionwithadecreaseintheSeebeckcoefficient absolutevalue.Inaddition,Bi2Se3compoundisfoundtoexhibitrelativelyhighroomtemperature powerfactorandfigureofmeritvaluesof2.13μW/m.k2.Inanattempttodeterminethefigureof meritZT,Bi2Se3seemstobethebestforroomtemperature,whereas,Teadditionathighvaluesmakes thesystemjustsuitableforhightemperatureapplication Read more

Thin films of Bi-based chalcogenides were prepared by pulsed laser deposition (PLD) technique according to the stoichiometric formula: Bi2(Se1−xTex)3. Their optical properties were studied aiming to find the suitable area of application and the optimum composition amongst the samples under study. X-ray diffraction analysis proved the crystallinity of the deposited samples; in addition, surface roughness and films homogeneity were studied ... Read more