Lukáš Hrdý

All projects

Kinetic Monte Carlo: sapphire growth

Atom-by-atom simulation of sapphire (α-Al₂O₃) thin-film growth by pulsed laser deposition, including dopants with tunable energetics.

Where
Student Faculty Grant (SFG), Dept. of Surface and Plasma Science, Charles University
Supervisor
doc. RNDr. Pavel Kocán, Ph.D.
When
02/2026 –

I wrote a kinetic Monte Carlo simulation of sapphire (corundum) growth by pulsed laser deposition (PLD) on a sheared hexagonal lattice with an implicit oxygen sublattice. It runs as an automated pipeline: simulation → structural evaluation (coordination, occupancy) → coverage-vs-time plots and 3D export.

I added other cations (dopants) whose binding energies and diffusion barriers can be tuned, so one can study how they change the film morphology, e.g. whether dopants cluster.

The code is Python (hot loops JIT-compiled with Numba) and handles grids of about 500 × 500 with thousands of layers within hours.

  • Al, coloured by height
  • dopant
Result of my kinetic Monte Carlo simulation: top 30 atomic levels of a 48 × 48 column cut from a 300 × 300, 1000-layer run. Growth at 1200 K, 100 Hz, 0.2 layer per pulse; dopants make up 3 % of the deposited cation flux.

Key results

  • Working kMC model of sapphire growth with tunable dopant energetics
  • Large runs: ~500 × 500 grid, thousands of layers, a few hours
  • Trend: a stronger dopant Ehrlich–Schwoebel barrier → dopants cluster