Tuning of electronic and optical properties of a predicted silicon allotrope: Hexagonal silicon h10 -Si

Theoretical investigation of the role of hydrogenation-induced strain in single-layer h10-Si

“…Therefore, in addition to uniaxial tensile strain, hydrogenation-induced equivalent strain can also continuously tune the light absorption spectrum in a wide range of 0.80 eV. Interestingly, the magnitude of the total shift is comparable to that in strain-tuned silicon 33 and black phosphorus, 47 but is larger than that in doped Si–Ge alloy. 48 On the other hand, with the hydrogenation concentration beyond 87.5%, the intensity of the VIS absorption peak is blunted.…”

“…Here, ε d is defined as the change rate of d , which is different from the conventional uniaxial tensile strain defined by the change rate of the c -axis. 33 In SL h 10-Si, ε d leads to a biaxial compressive strain, ε xy , of −0.6% on the a – b plane. The produced ε xy is close to that induced by a c -axis uniaxial tensile strain of about 10.5% in bulk h 10-Si, which triggers the electronic transition from an indirect to a direct band gap in bulk h 10-Si.…”

“…In the theoretical design of silicene, we have recently proposed SL h10-Si that can be exfoliated from the bulk allotrope. 33 SL h10-Si exhibits a honeycomb-like structure isostructural to the 2 Â 2 large honeycomb dumbbell silicene (LHDS) in Cahangirov's work. 13 It is worth noting that similar dumbbell-like features can be observed in previous experiments, 11,12 indicating that SL h10-Si is experimentally achievable.…”

“…In this paper, taking single-layer (SL) h 10-Si 33 as an example, we systematically investigate the evolution of the structural, electronic, and optical properties of 2D materials under hydrogenation by means of state-of-the-art first-principles calculations. First, we prove the hydrogenation-induced enhancement of the structural stability of SL h 10-Si, and a hydrogenation-induced electronic transition from an indirect- to a direct-gap semiconductor is observed in SL h 10-Si.…”

Quantum spin Hall effect in tilted penta silicene and its isoelectronic substitutions

“…Due to their advantageous electronic and optical properties, diamond-structure silicon and some other metastable bulk silicon allotropes have promoted the development of the semiconductor industry for decades. 1–7 However, the demand for miniaturization of nanoelectronic devices has increased the demand for low dimensional materials, especially low dimensional silicon materials. In recent years, silicene, which was proposed to share a similar honeycomb structure with graphene, has been successfully synthesized on various substrates.…”