Model for determination of mid-gap states in amorphous metal oxides from thin film transistors
Model for determination of mid-gap states in amorphous metal oxides from thin film transistors
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DOI：
10.1063/1.4808457
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发表时间：
2013-06
影响因子：
3.2
通讯作者：
S. Bubel;M. Chabinyc
中科院分区：
文献类型：
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作者：
S. Bubel;M. Chabinyc
金属氧化物半导体如非晶氧化锌（a-ZnO）及其与铟、镓、锡或铝的三元和四元氧化物合金中的电子态密度不同于非晶硅或无序材料如并五苯或P3 HT。许多基于ZnO的半导体表现出陡峭的受主尾态（陷阱DOS）衰减密度和接近导带能量（EC）的费米能级（EF）。考虑到薄膜晶体管（TFT）在累积模式下的操作，电子的准费米能级（Eq）甚至更接近EC。经典的解析TFT模拟使用简化EC−EF>“几个”kT，并且不能再现特征能量小于1/2 kT的指数尾态。我们证明了一个分析模型的尾部和深受主状态，有效的所有非晶金属氧化物，包括陷阱辅助跳跃的效果，而不是简单的渗流或迁移率边缘模型，占所观察到的场依赖迁移率。
The electronic density of states in metal oxide semiconductors like amorphous zinc oxide (a-ZnO) and its ternary and quaternary oxide alloys with indium, gallium, tin, or aluminum are different from amorphous silicon, or disordered materials such as pentacene, or P3HT. Many ZnO based semiconductors exhibit a steep decaying density of acceptor tail states (trap DOS) and a Fermi level (EF) close to the conduction band energy (EC). Considering thin film transistor (TFT) operation in accumulation mode, the quasi Fermi level for electrons (Eq) moves even closer to EC. Classic analytic TFT simulations use the simplification EC−EF> ‘several’kT and cannot reproduce exponential tail states with a characteristic energy smaller than 1/2 kT. We demonstrate an analytic model for tail and deep acceptor states, valid for all amorphous metal oxides and include the effect of trap assisted hopping instead of simpler percolation or mobility edge models, to account for the observed field dependent mobility.