Structural and physical effects of Mg-doping on p-type CuCrO2 and CuAl0.5Cr0.5O2 thin films
Structural and physical effects of Mg-doping on p-type CuCrO2 and CuAl0.5Cr0.5O2 thin films
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DOI：
10.1039/b926424h
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发表时间：
2010-07
影响因子：
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通讯作者：
Robert Bywalez;S. Götzendörfer;P. Löbmann
中科院分区：
文献类型：
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作者：
Robert Bywalez;S. Götzendörfer;P. Löbmann
采用溶胶-凝胶法制备了CuCrO2和CuAl0.5Cr0.5O2的掺镁薄膜，两者均具有沉积岩结构。在随后的两步退火过程中，通过x射线衍射监测了掺杂物对相发展的影响。当掺杂浓度在2.5 ~ 15%之间变化时，Mg会抑制结晶，稳定尖晶石相，防止热分解，从而增加了迟发岩膜中的杂质量。然而，Mg的掺杂使CuCrO2薄膜的p型电导率和透射率分别提高了2个数量级和16%。相反，Mg掺杂对CuAl0.5Cr0.5O2薄膜的性能几乎没有影响。该体系的seebeck系数甚至暗示随着掺杂浓度的增加载流子密度降低，这只能解释为作为强本征掺杂的天然缺陷的排出。然而，两种氧化物的带隙保持不变。
Magnesium doped thin films of CuCrO2 and CuAl0.5Cr0.5O2, both exhibiting delafossite structure, were synthesized via sol–gel processing. The influence of the dopant on the phase development during the subsequent 2-step annealing procedure was monitored by X-ray diffraction. Systematic variation of the dopant concentration between 2.5 and 15% revealed that the Mg inhibits crystallization and stabilizes spinel phases against thermal decomposition, whereby the amount of impurities in the delafossite films is increased. Nevertheless the p-type conductivity and surprisingly the transmittance of the CuCrO2 films were improved by Mg doping by two orders of magnitude and 16%, respectively. On the contrary the performance of the CuAl0.5Cr0.5O2 films hardly profits from Mg doping. The Seebeck-coefficients of this system even imply a decreasing charge carrier density with increasing dopant concentration, which can only be interpreted as an expulsion of the native defects acting as strong intrinsic doping. The band gap of both oxides remains constant, however.