|학술대회||2015년 봄 (05/14 ~ 05/15, 구미코)|
|발표분야||C. 에너지 재료|
|제목||Nanostructured n-type Cr/Cr2O3 Thin Films with Enhanced Thermoelectric Properties of by Reactive Sputtering Method|
|초록||Thermoelectric energy harvesting is the transformation of waste heat into useful electricity for applications — acquired the great interest for energy sustainability. The main obstacle is the low thermoelectric efficiency of materials for converting heat to electricity, quantified by the thermoelectric figure of merit, ZT. The best available n-type materials for use in mid-temperature (500–900 K) thermoelectric generators have a relatively low ZT of 1 or less, and so there is much interest in finding avenues for increasing this figure of merit .Chromium oxide (α-Cr2O3) is rather interesting material and belongs to the family of transition metal oxides. It is a wide band-gap semiconductor since its direct band-gap width is equal to 3.3eV [2,3]. It has a wide range of applications, i.e. α-Cr2O3 materials are used as catalysts, solar thermal energy collectors, as well as in black matrix films, liquid crystal displays [4,5], protective layers (corrosion and wear resistance of stainless steel) and adhesion promoters .However, It is found that the defect and transport properties in Cr2O3 are complicated. In generally, at high oxygen partial pressure, Cr2O3 shows p-type conductor with electrons holes and chromium vacancies while at low oxygen partial pressure, near the Cr/Cr2O3 equilibrium oxygen pressure, it changes to n-type semiconductor with electrons and chromium interstitials dominant. Moreover, thermoelectric properties of Cr2O3 thin films have not been sufficiently explored even if they are relatively easy to prepare.
In this present study, Cr/Cr2O3 thin films were grown onto Glass substrate by Reactive sputtering of chromium target in an argon and oxygen atmosphere at room temperature and annealed at temperatures ranging from 500oC to 700oC in air ambient for various time. The Crystalline structure, thickness, morphologies and carrier concentration of the deposited Cr/Cr2O3 thin films were measured by XRD, SEM and Hall measurement respectively. From the XRD, Cr/Cr2O3 films have polycrystalline nature. Thermoelectric properties for deposited and annealed films. However the experimental results showed that deposited Cr/Cr2O3 annealed at 700oC shows good thermoelectric properties, which are stably with increasing of measuring temperature and exhibits the power factor around 0.23x 10-4 W/K2m .All deposited thin films showed n-type conductivity, which is also confirmed by both Seebeck coefficient and hall effect measurement.
|소속||1chungnam national Univ., 2충남대|
|키워드||<P>Cr/Cr<SUB>2</SUB>O<SUB>3</SUB> thin film; Sputtering; Thermoelectric properties</P>|