Modulation of Remote Epitaxial Heterointerface by Graphene-Assisted Attenuative Charge Transfer

Abstract

Remote epitaxy (RE), substrate polarity can "penetrate" two-dimensional materials (2DMs) and act on the epi-layer, showing a prospective universal growth strategy. However, essentially, the role that 2DMs plays in RE has not been deeply investigated so far. Here, the RE of single-crystal films on the weakest polarity/iconicity substrate is realized to reveal its essence physical properties. Graphene facilitates attenuative charge transfer (ACT) from a substrate to epi-layer to construct remote interactions. Interfacial atoms are assembled into "incommensurate" epitaxial relationships through graphene to reduce misfit dislocations in the epilayer. Moreover, graphene reduces the atomic migration barrier, leading to a tendency toward a "layer-by-layer" growth mode. Such film growth mode is different with the conventional epitaxy (CE), and it is beneficial for the fast growth of epi-layers and the reduction of dislocations at coalescence boundaries. The insightful revelation of the role of graphene reveals the interface physics of RE and provides a more valuable guide to using 2DMs to expand three-dimensional materials (3DMs) for application in devices.

Robust SrTiO3 Passivation of Silicon Photocathode by Reduced Graphene Oxide for Solar Water Splitting

“…Numerous pinholes were present in STO film (RMS = 1.10 nm), which was in direct contact with Si, whereas a very smooth layer with atomic-scale surface roughness (RMS = 0.34 nm) was observed for STO overgrown on rGO-buffered Si. The lower diffusion energy barrier of rGO compared to that of SiO 2 enables the depositing materials to more easily migrate and rearrange on the graphene-based surface, which otherwise tend to desorb from the SiO 2 surface given the higher diffusion barrier. , …”

“…The lower diffusion energy barrier of rGO compared to that of SiO 2 enables the depositing materials to more easily migrate and rearrange on the graphene-based surface, which otherwise tend to desorb from the SiO 2 surface given the higher diffusion barrier. 42,43 After deposition of the STO layer, the light reflected off the sample surface gets reduced compared to bare Si in the ultraviolet, visible, and near-infrared regions (see UV−vis spectra in Figure S5). The improvement of light absorption could be helpful in terms of solar light harvesting as the planar silicon inherently reflects away a certain amount of photons which then cannot be used for the charge carrier generation.…”

Influence of Graphene Stability on III-Nitride Remote Epitaxy for Exfoliation

“…In recent years, two-dimensional (2D) materials (e.g., graphene and h-BN) have been used as a transition layer on the substrate during III-nitrides epitaxy. – The existence of the 2D material between the substrate and the epi-layer can tolerate the mismatch of lattice constants and thermal expansion coefficients. Different from traditional epitaxy, there is only a weak van der Waals force between the substrate and the epi-layer on both sides of the 2D transition layer.…”

Pulsed-Mode Metalorganic Vapor-Phase Epitaxy of GaN on Graphene-Coated c-Sapphire for Freestanding GaN Thin Films

“…Manufacturing high-quality inorganic thin films on large-area flexible substrates is a key technology required for flexible devices such as wearable sensors, flexible displays, , and electronic devices . One promising approach for the fabrication of flexible devices using inorganic thin films is to grow epitaxial thin films on two-dimensional (2-D) layered materials such as graphene and h -BN since the 2-D materials offer weak bonding with as-grown films for easy exfoliation of epilayers from 2-D materials. ,− In particular, an epitaxial method called remote epitaxy enables us to grow single-crystalline thin films on graphene-coated polar substrates where the partially screened electrostatic potential of the substrate allows the epitaxial relationship between the substrate and the epilayer. , Recent studies have demonstrated successful remote epitaxy of single-crystalline thin films for various III–V, , III–N, − and complex-oxide materials, showing its potential for providing flexible and high-quality material platforms for future device applications. − …”