Why is this important?
Photonics devices based on the integration of III-V materials (in this case is GaAs) on Si.
What needs to be done?
Heteroepitaxial growth using MBE utilizing 2D material, owning to its VdW bonding which yields to accomodation to lattice mismatch between 3D-2D material.
What has been done already?
MBE-grown GaAs NWs on graphene/Si substrate (A. M. Munshi et al, Nano Lett.2012, 12, 4570), MOCVD-grown InAs/In(x)Ga(1-x)As NWs on graphene (Nano Lett. 2013, 13, 1153) and GaAs/Si using layered GaSe ( , J. Cryst. Growth 1995, 150, 685).
Goal of the Research Project
Using graphene as a buffer layer in realizing VdW epitaxial growth of GaAs on Si
First, Y. Alaskar et al calculated surface energy of the graphene buffer layer with Ga and As prelayer; adsorption and migration energy of Al, Ga, In and As on graphene; The experimental is divided in fabrication (mechanical exfoliation of graphene and growing using MBE) and characterization (FESEM, AFM, Raman spectroscopy and XRD)
Theoretical result will not be presented in here, and instead, we focus on experimental result: (i) due to the low surface energy of graphene triggering high tension toward GaAs and (ii) low adsorption and mitigation energy of Ga and As on graphene at high temperature, island growth (3D) is formed instead of single crystal (2D) of GaAs
Challenges and Bottlenecks
Developing understanding of VdW interaction between GaAs/graphene/Si
Opportunities and Workarounds
Two-step growth is employed to investigate graphene using Ga- or As- prelayer.
Important: Growth morphology-surface energy, nucleation step-thin film properties, low surface energy of graphene, low adsorption energy of Ga and As, nucleation site, surface energy-adsorption energy, surface energy-growth temperature-wettability-nucleation process,