Role of vacancy defects on the lattice thermal conductivity in In2O3 thermoelectric nanocrystals: a positron annihilation study
Role of vacancy defects on the lattice thermal conductivity in In2O3 thermoelectric nanocrystals: a positron annihilation study
复制标题
空位缺陷对 In2O3 热电纳米晶晶格热导率的影响：正电子湮没研究
DOI：
10.1007/s10853-018-2544-5
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发表时间：
2018
影响因子：
4.5
通讯作者：
X. F. Tang
中科院分区：
文献类型：
--
作者：
H. F. He;B. Zhao;N. Qi;B. Wang;Z. Q. Chen;X. L. Su;X. F. Tang
High purity $$\hbox {In}_2\hbox {O}_3$$In2O3 nanopowders were subjected to different thermal treatments to investigate the role of defects on the lattice thermal conductivity. The powders were first treated by spark plasma sintering (SPS) at $$700\,^{\circ}\hbox {C}$$700∘C and annealed in air between 700 and $$1300\,^{\circ}\hbox {C}$$1300∘C. X-ray diffraction measurements show that the samples are single phase, and the diffraction peaks become sharper with increasing of annealing temperature, indicating improvement in crystallinity and increase in grain size. The $$\hbox {In}_2\hbox {O}_3$$In2O3 nanopowders were also treated by SPS sintering at different temperatures without subsequent annealing. On the contrary, the average grain size of $$\hbox {In}_2\hbox {O}_3$$In2O3 treated by SPS has no obvious change with the increase in sintering temperatures. Positron annihilation measurements reveal large amounts of monovacancies and vacancy clusters in the $$\hbox {In}_2\hbox {O}_3$$In2O3 nanocrystals. The monovacancies gradually recover and the vacancy clusters transform into smaller vacancies with increasing annealing or sintering temperatures. The lattice thermal conductivity increases with the increase in annealing or sintering temperature, which shows close correlation with the recovery of vacancy defects after heat treatment. This gives us strong evidence that vacancy defects play an important role on the suppression of lattice thermal conductivity in nanostructured thermoelectric materials.
High purity $$\hbox {In}_2\hbox {O}_3$$In2O3 nanopowders were subjected to different thermal treatments to investigate the role of defects on the lattice thermal conductivity. The powders were first treated by spark plasma sintering (SPS) at $$700\,^{\circ}\hbox {C}$$700∘C and annealed in air between 700 and $$1300\,^{\circ}\hbox {C}$$1300∘C. X-ray diffraction measurements show that the samples are single phase, and the diffraction peaks become sharper with increasing of annealing temperature, indicating improvement in crystallinity and increase in grain size. The $$\hbox {In}_2\hbox {O}_3$$In2O3 nanopowders were also treated by SPS sintering at different temperatures without subsequent annealing. On the contrary, the average grain size of $$\hbox {In}_2\hbox {O}_3$$In2O3 treated by SPS has no obvious change with the increase in sintering temperatures. Positron annihilation measurements reveal large amounts of monovacancies and vacancy clusters in the $$\hbox {In}_2\hbox {O}_3$$In2O3 nanocrystals. The monovacancies gradually recover and the vacancy clusters transform into smaller vacancies with increasing annealing or sintering temperatures. The lattice thermal conductivity increases with the increase in annealing or sintering temperature, which shows close correlation with the recovery of vacancy defects after heat treatment. This gives us strong evidence that vacancy defects play an important role on the suppression of lattice thermal conductivity in nanostructured thermoelectric materials.