I want to know what will be took into consideration and their priority of choosing substrate for epitaxial film growth.
Specifically, I want to change the substrate to let one of my peak, which is not obvious in the current XRD result, to become strong. Then what aspect should I consider to achieve this?
Dear Zhimin Qi
Generally, the following factors are needed to be considered in epitaxial growth:
- Growth mechanism or growth mode
- Strain due to lattice mismatch and thickness of epitaxial layer(s)
- Thermal lattice expansion
- Interdiffusion between atoms in epitaxial layer(s) and substrate
Apart from these, the growth condition is very essential. We can effectively control the growth mechanism and interdiffusion through the growth condition such as growth temperature and growth rate.
The substrate can only help to stabilise metastable phases using (or avoiding) strain from a theoretical point of view. However, in reality many substrates have "dirty" surfaces to start with and so couple less than ideal with the layer. For instance for GaAs on GaAs by MBE you still get 3D growth at the start due to the difficulties of completely removing the GaAs native oxid.
Thank you for your response, so with the surface not possible to be clean enough, I know there will be effect on nucleation. However, with the PLD as a physical depostion process, even with all the factor to be considered can I consider that whether or not I will have the phase is depend on the temperature and reaction time ( Kinetically process)? Then it is just a matter of whether the phase is favorable or not?
The database https://materialsproject.org suggests substrates for different compounds.
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