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 إقراء المزيد

Polycrystalline bulk samples of Bi2(Se1−xTex)3 system with x=0.0–0.9 were prepared by the conventional melting method. Successfully and cheaply, Se atoms were replaced by Te atoms to get Bi2Se3-Bi2Te3 or even Bi2Te3 alone. Difference of mass and size between Te and Se atoms is expected to result in interesting properties in the Bi2(Se1−xTex)3 system. All compounds showed a metalsemiconductor conductivity transition. ... إقراء المزيد