Microscopic description of the thermalization process during pulsed laser deposition of aluminium in the presence of argon background gas
The presence of background gases is typical in most pulsed laser deposition (PLD) applications and there is a need for methods which do not suffer from the oversimplified assumption of collisionless transfer of the target atoms onto the substrate in analytical descriptions. In this work, we give a microscopic description of a thermalization process by following the history of each ablated particle by Monte Carlo calculations. TRIM code (SRIM2010), which is capable of quantum mechanical treatment of ion-atom collisions, has been used in our simulations. Various kinetic parameters of ablated Al ions during target-to-substrate transfer have been calculated to demonstrate the efficient role of background gas atoms in thermalization of ions. Moreover, the growing parameters of interest in PLD have been calculated to achieve the optimal deposition conditions in the presence of a background gas. A base pressure of 1 × 10-1 Torr and 2-3 cm of target-to-substrate distance have been found to be the optimal conditions in PLD of Al in Ar gas environment. Our model can be used to obtain the first estimates of nonreactive PLD parameters, such as the background gas pressure and the target-to-substrate distance for the growth of even more complex materials in the presence of different background gases.