Materials try to minimise the total energy density, which consists of chemical, strain and surface enthalphy, so the latter will play a crucial role in the growth also during epitaxy.

Dear Dr. Bijit Choudhuri

Peace be upon you

Samples usually grow in the direction which has a low surface energy, especially if the rate of deposition is slow and the used substrate is not preheated. This is due to that all materials tend to have a minimum energy.

Good luck

Thank you sir for your replies