Disordered stoichiometric nanorods and ordered off- stoichiometric nanoparticles in n-type thermoelectric BiTe.Se
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چکیده
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. N-type Bi 2 Te 2.7 Se 0.3 bulk thermoelectric materials with peak ZT values up to $1 were examined by transmission electron microscopy and electron diffraction. Two nanostructural features were found: (i) a structural modulation of $10 nm, which consisted of nanorods with crystalline and nearly amorphous regions, having the rod axes normal to (0,1,5)-type planes, and wave vector normal to (1,0,10)-type planes and (ii) non-stoichiometric ordered Bi-rich nanoparticles. The presence of the structural modulation was not influenced by the ion milling energy or temperature in this study while the non-stoichiometric ordered nanoparticles were only observed when ion milling at low temperatures and low energy was used. It is proposed that both the structural modulation of $10 nm and the presence of non-stoichiometric nanoparticles are responsible for the low lattice thermal conductivity ($0.6 W/mK) of the Bi 2 Te 2.7 Se 0.3 bulk thermoelectric materials studied.
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تاریخ انتشار 2013