High-temperature oxidation behavior of thermoelectric SnSe

作者：Li Yi; He Bin; Heremans Joseph P^*; Zhao Ji Cheng^*

来源：Journal of Alloys and Compounds, 2016, 669: 224-231.

DOI：10.1016/j.jallcom.2016.01.258

• Thermoelectric materials
• Intermetallics
• Oxidation
• Phase diagrams
• Metallography
• X-ray diffraction

SnSe is a semiconductor compound reported to possess very high thermoelectric ZT values at 600 degrees C e700 degrees C. Oxidation and sublimation are of significant concern at such temperatures. The oxidation behavior of SnSe at four temperatures between 600 degrees C and 700 degrees C in atmospheric air was investigated by monitoring the weight change as a function of time, as well as by characterizing the oxidized samples using optical microscopy, SEM with EDS, and powder XRD. The results show that SnSe oxidizes very rapidly at 600 degrees C-700 degrees C to form SnO2 and possibly Sn(SeO3)(2). Sublimation of Se and Se oxides is also observed. At 600 degrees C the consumption of Sn from SnSe to form SnO2 drives the composition to be Se rich. A layer of SnSe2 forms between the oxides and SnSe. At -650 degrees C, the consumption of Sn likely leads to the formation of a transient liquid phase, which significantly accelerates both oxidation and sublimation. It is concluded that SnSe needs to be used under vacuum or with a protective coating such as pure Si.

• 出版日期2016-6-5