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Title: Designing substrates for silicene and germanene: First-principles calculations

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Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 7; Related Information: CHORUS Timestamp: 2016-08-08 18:10:42; Journal ID: ISSN 2469-9950
American Physical Society
Country of Publication:
United States

Citation Formats

Chen, M. X., Zhong, Z., and Weinert, M.. Designing substrates for silicene and germanene: First-principles calculations. United States: N. p., 2016. Web. doi:10.1103/PhysRevB.94.075409.
Chen, M. X., Zhong, Z., & Weinert, M.. Designing substrates for silicene and germanene: First-principles calculations. United States. doi:10.1103/PhysRevB.94.075409.
Chen, M. X., Zhong, Z., and Weinert, M.. Mon . "Designing substrates for silicene and germanene: First-principles calculations". United States. doi:10.1103/PhysRevB.94.075409.
title = {Designing substrates for silicene and germanene: First-principles calculations},
author = {Chen, M. X. and Zhong, Z. and Weinert, M.},
abstractNote = {},
doi = {10.1103/PhysRevB.94.075409},
journal = {Physical Review B},
number = 7,
volume = 94,
place = {United States},
year = {Mon Aug 08 00:00:00 EDT 2016},
month = {Mon Aug 08 00:00:00 EDT 2016}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevB.94.075409

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Cited by: 8works
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  • The O{sub 2} dissociation and O atoms adsorption on free-standing germanene are studied by using first-principles calculations in this paper. Compared with the extremely active silicene in oxygen atmosphere, germanene is found to be less active due to an energy barrier for dissociation of about 0.57 eV. Moreover, the dissociated oxygen atom follows two opposite migration pathways on the germanene surface, which is quite different from the case of silicene. Furthermore, the migration and desorption of O atoms at room temperature are relatively difficult due to the strong Ge-O bonding, resulting in the formation of germanium oxides. Our results reveal themore » interplay between germanene and O{sub 2} and suggest the enhanced stability of germanene in oxygen atmosphere compared with silicene.« less
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  • Silicene on metal silicides poses promise for direct integration of silicene into electronic devices. The details of the metal silicide-silicene interface, however, may have significant effects on the electronic properties. In this work, the electronic properties of silicene on NiSi 2(111) and hydrogenated NiSi 2(111) (H:NiSi 2) substrates, as well as hydrogenated silicene (H:silicene) on a NiSi 2(111) substrate, were simulated using first principles methods. The preferred Si surface termination of NiSi 2 was determined through surface energy calculations, and the band structure and density of states (DOS) were calculated for the two-dimensional silicene and H:silicene layers. Hydrogenating NiSi 2more » lowered the binding energy between silicene and the substrate and resulting in partial decoupling of the electronic properties. Relaxed silicene on H:NiSi 2 showed a small band gap opening of 0.14 eV. Silicene on H:NiSi 2 also had a calculated electron effective mass of 0.08m 0 and Fermi velocity of 0.39×10 6 m/s, which are similar to the values for freestanding silicene. H:silicene on NiSi 2 retained its band structure and DOS compared to freestanding H:silicene. The band gap of H:silciene on NiSi 2 was 1.97 eV and is similar to freestanding H:silicene band gap of 2 eV. As a result, this research showed that hydrogenation may be a viable method for decoupling a silicene layer from a NiSi 2(111) substrate to tune its electronic properties.« less
  • Ion implantation has been widely used in the semiconductor industry for decades to selectively control electron/hole doping for device applications. Recently, experimental studies on ion implantation into more structurally and electronically complex materials have been undertaken in which defect generation has been used to control a variety of functional phenomena. Of particular interest, are recent findings demonstrating that low doses of low energy helium ions into single crystal films can be used to tailor the structural properties. These initial experimental studies have shown that crystal symmetry can be continuously controlled by applying increasingly large doses of He ions into amore » crystal. The observed changes in lattice structure were then observed to correlate with functional changes, such as metal-insulator transition temperature2 and optical bandgap3. In these preliminary experimental studies, changes to lattice expansion was proposed to be the direct result of chemical pressure originating predominantly from the implanted He applying chemical pressure at interstitial sites. However, the influence of possible secondary knock-on damage arising from the He atoms transferring energy to the lattice through nuclear-nuclear collision with the crystal lattice remains largely unaddressed. In this work, we focus on a SrRuO3 model system to provide a comprehensive examination of the impact of common defects on structural and electronic properties, obtain calculated defect formation energies, and define defect migration barriers. Our model indicates that, while interstitial He can modify the crystal properties, a dose significantly larger than those reported in experimental studies would be required. The true origin of the observed structural changes is likely the result of a combination of secondary defects created during He implantation. Of particular importance, we observe that different defect types can generate greatly varied local electronic structures and that the formation energies and migration energy barriers vary by defect type. Thus, we may have identified a new method of selectively inducing controlled defect complexes into single crystal materials. Development of this approach would have a broad impact on both our ability to probe specific defect contributions in fundamental studies and allow a new level of control over functional properties driven by specific defect complexes.« less