Vacancies and dopants in two-dimensional tin monoxide: An ab initio study

Abstract

Layered tin monoxide (SnO) offers an exciting two-dimensional (2D) semiconducting system with great technological potential for next-generation electronics and photocatalytic applications. Using a combination of first-principles simulations and strain field analysis, this study investigates the structural dynamics of oxygen (O) vacancies in monolayer SnO and their functionalization by complementary lightweight dopants, namely C, Si, N, P, S, F, Cl, H and H2. Our results show that O vacancies are the dominant native defect under Sn-rich growth conditions with active diffusion characteristics that are comparable to that of graphene vacancies. Depending on the choice of substitutional species and its concentration within the material, significant opportunities are revealed in the doped-SnO system for facilitating n/ptype tendencies, work function reduction, and metallization of the monolayer. N and F dopants 2 2 are found to demonstrate superior mechanical compatibility with the host lattice, with F being especially likely to take part in substitution and lead to degenerately doped phases with high open-air stability. The findings reported here suggest that post-growth filling of O vacancies in Sn-rich conditions presents a viable channel for doping 2D tin monoxide, opening up new avenues in harnessing defect-engineered SnO nanostructures for emergent technologies.

Fermi level depinning via insertion of a graphene buffer layer at the gold–2D tin monoxide contact

“…Table 1 displays the computed work functions, and those of the pristine materials are consistent with values in the literature [49][50][51]. The pristine Au (111) surface exhibits a slightly lower work function than mSnO.…”

Effects of Defect on Work Function and Energy Alignment of PbI2: Implications for Solar Cell Applications

“…The intrinsic defects, like atomic vacancies, are inevitably introduced in PbI 2 during the preparation processes. The doping of vacancies has a great influence on the electronic properties, such as enhancing light absorption for photocatalysis and acting as molecular adsorption sites and channels for electron and hole transfer. , Here, we investigated the effect of various V I (V I‑1 , V I‑2 , V I‑3 ) with concentrations of 1.38%, 9.72%, and 19.44% on the structural and electronic properties of ML-PbI 2 . The formation energies E f were calculated and listed in Table .…”

Layer-dependent electronic and optical properties of tin monoxide: a potential candidate in photovoltaic applications

“…The structure of the bulk SnO unit cell adopts the tetragonal space group with P4/nmm symmetry, and the lattice parameters are a = b = 3.8 Å and c = 4.84 Å, which are in agreement with those of previous reports. 19,20,[31][32][33][34] SnO layers are separated by a van der Waals gap of 2.51 Å along the [001] stacking direction, which is mainly induced by the dipole-dipole interaction of interlayer lone pair Sn 5s electrons that point toward the interlayer spacing. Each layer adopts a Sn-O-Sn sequence.…”

“…Until now, advanced synthesis methods like hydrothermal and intercalation, 28 liquid phase exfoliation, 26,27 mechanical exfoliation 29,30 and pulsed laser deposition 19 have successfully realized precise control over the thickness of the synthesized SnO nanosheets. That is to say, the electronic and optical properties of SnO, such as band gaps that can range from B4.0 eV to B0.7 eV from monolayer SnO to bulk SnO and adsorption coefficients, [31][32][33][34] can be regulated for realizing applications of SnO in different fields and further improving the performance of the SnO-based electronic devices. Due to the fast carrier transport and separation efficiency, as well as the wide range of tunable band gaps in SnO sheets, one would expect a fine performance of SnO sheets in solar cell applications.…”