Electrical properties of thermoelectric cobalt Ca3Co4O9 epitaxial heterostructures
Electrical properties of thermoelectric cobalt Ca3Co4O9 epitaxial heterostructures
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热电钴Ca3Co4O9外延异质结构的电性能
DOI：
10.1063/1.4795767
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发表时间：
2013-03-21
影响因子：
3.2
通讯作者：
Yang, Guozhen
中科院分区：
文献类型：
--
作者：
Guo, Haizhong;Wang, Shufang;Yang, Guozhen
由层状钴氧化物制造的异质结构为热电应用提供了实质性的优势。采用脉冲激光沉积法在SrTiO 3衬底上制备了C轴取向的Ca 3Co 4 O 9（CCO）薄膜和Ca 3Co 4 O 9/SrTi0.993Nb0.007O3 p-n异质结。在Ca 3Co 4 O 9薄膜上进行的面内电阻率，热电势和磁性能的测量被发现是可比的ab-平面的单晶由于良好的取向的膜。研究了Ca_3Co_4O_9/SrTi_（0.993）Nb_（0.007）O_3 p-n异质结的电输运性质与温度的关系。在正向偏压下，该结在不同的温度范围内表现出两种不同的输运机制：在100-380 K温度范围内的肖特基势垒隧穿机制，以及在10 - 100 K的低偏压下的隧穿机制和高偏压下的热发射机制。但是，在低反向偏压的情况下，陷阱辅助隧穿过程应该被考虑。
Heterostructures fabricated from layered cobalt oxides offer substantial advantages for thermoelectric applications. C-axis-oriented Ca3Co4O9 (CCO) thin films on SrTiO3 substrates and Ca3Co4O9/SrTi0.993Nb0.007O3 p-n heterojunctions were fabricated by pulsed laser deposition. The measurements of in-plane resistivity, thermopower, and magnetic properties performed on the Ca3Co4O9 thin films were found to be comparable to ab-plane those of the single crystals due to good orientation of the films. The temperature dependence of the electrical transport properties of Ca3Co4O9/SrTi0.993Nb0.007O3 p-n heterojunction was also investigated. The junction shows two distinctive transport mechanisms at different temperature regimes under forward bias: tunneling across the Schottky barrier in the temperature range of 100-380 K, and tunneling mechanism at low bias and thermal emission mechanism at high bias between 10 and 100 K. However, for the case of low reverse bias, the trap assisted tunneling process should be consi...