Quantum Confinement Effect on the Band Structure of HfSe2: a First-Principle Study
Icuk Setiyawati1*, Yu-Hui Tang1
1Physics, National Central University, Zhongli,Taoyuan, Taiwan
* Presenter:Icuk Setiyawati
The transition metal dichalcogenide (TMD) semiconductor has remarkable properties that overcome the inability or the lack of the band gap in graphene [1], which offers the enormous exciting possibilities for electronic devices application. The group VIB TMDs (Mo, W)X2 with a 2H structure, has been extensively studied to have a great impact on nanoelectronic devices [2-4], despite their low carrier mobility (~40 cm2/Vs) comparing to graphene. Other TMD semiconductors, i.e group IVB (Hf, Zr)X2, with a 1T structure has potentially better properties of higher mobility (~3500 cm2/Vs) comparing to those VIB TMDs group [5].
Different from the multi-layer graphene which band gap weakly depends on the interlayer coupling, TMDs exhibit the van der Waals (vdW-like) interactions and the layer-dependent band gap [6,7]. In this study, we theoretically investigate the 1T-HfSe2 using the density functional theory (DFT) calculation. The indirect band gap varies from Γ-L (Bulk) to Γ-M (few-layered). We also investigate the quantum confinement effect, especially for the stripe-shaped of 6 Layer HfSe2, and further calculate the variation of band structure with respect to the stripe size. This work is supported by the Ministry of Science and Technology (106-2112-M-008-011-), the National Center for Theoretical Sciences, and the National Center for High-performance Computing (NCHC).

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Keywords: quantum confinement, band structure, First Principle Study