Spontaneous Non-stoichiometry and Ordering in Degenerate but Gapped Transparent Conductors
Spontaneous Non-stoichiometry and Ordering in Degenerate but Gapped Transparent Conductors
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DOI：
10.1016/j.matt.2019.05.014
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发表时间：
2019-07
期刊：
影响因子：
18.9
通讯作者：
O. Malyi;M. Yeung;K. Poeppelmeier;C. Persson;A. Zunger
中科院分区：
文献类型：
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作者：
O. Malyi;M. Yeung;K. Poeppelmeier;C. Persson;A. Zunger
我们强调了一类材料的道尔顿的观点，化合物在低温下保持整数化学计量的例外，并使用这种行为来选择有序的空位化合物（OVC）之间的载流子浓度，透明度和相稳定性，透明导体（TC）至关重要的想要的妥协。我们发现，载流子在导带（CB）的简并带隙的BaNbO 3，Ca 6Al 7 O 16，和Ag 3Al 22 O34化合物可以引起一个自我调节的不稳定性，从而形成阳离子空位，因为一小部分的CB电子衰变到空穴状态形成的空缺，这种电子-空穴复合抵消了正能量与空缺键断裂。这种费米能级诱导的自发非化学计量比可以导致形成具有不同光电性质的OVC，并且在不同的化学势范围内稳定。因此，我们展示了如何在透明性，导电性和稳定性的相反趋势之间确定机会之窗以设计TC。
We highlight a class of materials representing an exception to the Daltonian view that compounds maintain integer stoichiometry at low temperatures and use this behavior to select ordered vacancy compounds (OVCs) striking a wanted compromise between carrier concentration, transparency, and phase stability, crucial for transparent conductors (TCs). We show that carriers in the conduction band (CB) of degenerate gapped BaNbO3, Ca6Al7O16, and Ag3Al22O34compounds can cause a self-regulating instability, whereby cation vacancies form exothermically because a fraction of the CB electrons decays into the hole states formed by such vacancies, and this electron-hole recombination offsets the positive energy associated with vacancy bond breaking. This Fermi level-induced spontaneous non-stoichiometry can lead to the formation of OVCs with different optoelectronic properties and stable in different ranges of chemical potentials. Thus, we demonstrate how a window of opportunity can be determined between opposing tendencies of transparency, conductivity, and stability to design TCs.