Heterostructures composed of two-dimensional materials open new avenues for advancing semiconductor technology, particularly in the development of energy-efficient tunnel field effect transistors (TFETs). Here, we employ density functional theory calculations to investigate the electronic behavior of WTe₂/ZrS₂ heterostructures having diverse dimensions and arrangement motifs. Our simulations suggest that the topmost valence band of WTe₂ overlaps with the bottommost conduction band of ZrS₂, giving rise to the broken gap or type-III band alignment, which is favorable for fabricating TFETs. Using first-principles molecular dynamics simulations, the temperature effect on the electronic properties is studied, demonstrating that the broken gap band alignment is preserved at 300 K. Furthermore, the electronic properties of the heterostructures are shown to be affected by external electric fields: positive electric fields increase the overlap between the valence and conduction states, whereas negative electric fields lead to the opposite effect. Interestingly, a Rashba-type spin splitting is observed in the topmost valence band, and the Rashba energy is slightly influenced by the presence of external electric fields. Overall, our study sheds light on the inherent characteristics of WTe₂/ZrS₂ heterostructures and can be valuable for fabricating TFETs with optimal performance.

中文翻译：

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释放 2D WTe2/ZrS2 范德华异质结构在隧道场效应晶体管中的潜力：破隙带对准和电场效应


由二维材料组成的异质结构为推进半导体技术开辟了新的途径，特别是在开发节能隧道场效应晶体管 （TFET） 方面。在这里，我们采用密度泛函理论计算来研究具有不同维度和排列基序的 WTe₂/ZrS₂ 异质结构的电子行为。我们的模拟表明，WTe₂ 的最顶部价带与 ZrS₂ 的最底部导带重叠，产生断裂间隙或 III 型带对齐，这有利于制造 TFET。使用第一性原理分子动力学模拟，研究了温度对电子特性的影响，证明在 300 K 时保留了断裂的间隙带对齐。此外，异质结构的电子特性受外部电场的影响：正电场增加价态和导通态之间的重叠，而负电场导致相反的效果。有趣的是，在最顶部的价带中观察到 Rashba 型自旋分裂，并且 Rashba 能量受到外部电场存在的轻微影响。总体而言，我们的研究阐明了 WTe₂/ZrS₂ 异质结构的固有特性，对于制造具有最佳性能的 TFET 很有价值。