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锗烷因其合适的带隙、较高的电子迁移速率、较好的环境稳定性、较小的电噪声和超薄的几何结构, 有望取代现有硅基或锗基材料成为下一代半导体器件的理想载体. 基于密度泛函理论和非平衡格林函数的第一性原理方法, 研究了不同构型和浓度的氢空位簇对锗烷电子结构及锗烷中四硫富瓦烯(tetrathiafulvalene, TTF)分子掺杂性能的影响. 计算结果表明, 不同构型氢空位簇的引入可诱导Germanane Dehydrogenated-xH(G D–xH) 体系产生不同性质的磁性, 且磁矩大小亦与Lieb定理的预测结果相符, 并能在G D-xH( x= 1, 4, 6) 体系自旋向下的能带结构中实现由缺陷态引起的类p型半导体掺杂效应, 其电子激发所需的能量则会随着体系脱氢浓度的升高而不断降低. 吸附TTF分子后, G/TTF和G D-xH/TTF ( x= 1, 2, 6)体系表现出分子掺杂效应, 且G D-xH/TTF ( x= 1, 6)体系因分子轨道与缺陷态的杂化作用, 可在自旋向上与自旋向下的能带结构中形成不同的掺杂类型. 进一步的量子输运计算还表明, Armchair和Zigzag类型的锗烷基器件表现为明显的各向同性, 且TTF分子吸附所导致的载流子掺杂可大幅提高其 I-V特性.Germanane is expected to substitute for existing silicon-based or germanium-based material. Germanane is regarded as an ideal candidate for next-generation semiconductor material due to its suitable band gap, high electron mobility, better environmental stability, small electrical noise and ultrathin geometry. In this work, the effects of different configuration and concentration of hydrogen vacancy cluster on the electronic properties of germanane and its molecular doping are systematically investigated through the first-principles method based on density functional theory and none-quilibrium Green’s function. The results show that the hydrogen vacancy clusters with different configurations can induce magnetism with different characteristics in Germanane Dehydrogenated-xH(G D-xH) system, and the magnetic moments are consistent with the predictions of Lieb’s theorem. Moreover, the p-type-liked doping effects caused by defective state under G D-xH( x= 1, 4, 6) systems can be realized in their spin-down band structures. The corresponding energy values for exciting electron would gradually decrease with the increase of the concentration of hydrogen vacancy clusters under different configurations. After adsorbing tetrathiafulvalene (TTF) molecules, G/TTF and G D-xH/TTF ( x= 1, 2, 6) systems exhibit molecular doping characteristics induced by the TTF molecules. More importantly, for G D-xH/TTF ( x= 1, 6) system, the different molecular doping types can be introduced in spin-up and spin-down band structures due to the hybridization composed of molecular orbitals and defective states under spin polarization. Further calculations of their transport properties indicate that germanane-based device with Armchair and Zigzag configurations both exhibit intensive isotropy, and the performance of I-Vcharacteristics can be dramatically enhanced owing to the carrier doping by TTF adsorption.
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Keywords:
- germanane/
- defect/
- molecular adsorption/
- electronic properties
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参数 Germanane GD-1H GD-2H GD-4H GD-6H $ \mu /{\mu }_{{\rm{B}}} $ 0 1.000 0 2.000 0 ${d}_{ {\rm{G} }{\rm{e} }\text{—}{\rm{H} } }/$Å 1.561 1.561—1.568 1.562—1.567 1.562—1.567 1.564—1.570 ${d}_{ {\rm{G} }{\rm{e} }\text{—}{\rm{G} }{\rm{e} } }$/Å 2.467 2.465—2.487 2.345—2.493 2.430—2.492 2.415—2.492 Δ/Å 0.725 0.726 0.733 0.734 0.735 
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参数 G/TTF GD-1H/TTF GD-2H/TTF GD-4H/TTF GD-6H/TTF $ {E}_{{\rm{a}}{\rm{d}}} $/eV 0.583 0.889 0.766 0.895 1.230 $ \mu $/$ {\mu }_{{\rm{B}}} $ 0 1.000 0 2.000 0 d/Å 4.592 4.294 4.307 3.737 3.527 ${d}_{ {\rm{G} }{\rm{e} }\text{—}{\rm{G} }{\rm{e} } }$/Å 2.468—2.470 2.467—2.523 2.384—2.501 2.469—2.506 2.423—2.517 ${d}_{ {\rm{G} }{\rm{e} }\text{—}{\rm{H} } }$/Å 1.560—1.568 1.563—1.571 1.563—1.571 1.563—1.577 1.563—1.570 Δ/Å 0.735 0.738 0.734 0.739 0.736 Q/e 0.029 0.392 0.195 0.230 0.200 下载:
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[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38]
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