44 citations · 229 across the 25 of their papers we have counts for
18 papers · 1 filter
Tiling decomposition multiplicity predicts stability of GaN(0001) surface reconstructions
Tetsuji Kuboyama, Akira Kusaba, Karol Kawka +1
The stable adatom configurations of a semiconductor surface have traditionally been sought by sampling: density functional theory (DFT) energies steer a heuristic or Bayesian searc…
Hydrogen at GaN(0001) surface control of Fermi level pinning: Mg activation of p-type conductivity -- Nakamura process deciphered
Konrad Sakowski, Pawel Strak, Pawel Kempisty +2
Ab initio calculations were used to disentangle the mystery of Nakamura activation of p-type in Mg doped MOVPE grown gallium nitride, the key process leading to the 2014 Nobel Priz…
PyAPX: Python toolkit for atomic configuration pattern exploration
Akira Kusaba, Tetsuji Kuboyama, Karol Kawka +2
In materials discovery, the integration of first-principles calculations with machine learning techniques has been actively studied for two key tasks: crystal structure prediction,…
Limited Diffusion of Silicon in GaN: A DFT Study Supported by Experimental Evidence
Karol Kawka, Pawel Kempisty, Akira Kusaba +4
Silicon (Si) is the primary donor dopant in gallium nitride (GaN), introduced through epitaxial growth or ion implantation. However, precise control over Si diffusion remains a cri…
Charge control of semiconductor surfaces as elucidated by ab initio calculations a review
Stanisław Krukowski, Pawel Kempisty, Pawel Strak
Recent progress in the investigations of the charge role in semiconductor surfaces is reviewed.
Exploration of stable atomic configurations in graphene-like BCN systems by Bayesian optimization
Taichi Hara, Akira Kusaba, Yoshihiro Kangawa +4
h-BCN is an intriguing material system where the bandgap varies considerably depending on the atomic configuration, even at a fixed composition. Exploring stable atomic configurati…
Polarization spontaneous and piezo: fundamentals and their implementation in ab initio calculations
Pawel Strak, Pawel Kempisty, Konrad Sakowski +5
Fundamental properties of spontaneous and piezo polarization are reformulated and critically reviewed. It was demonstrated that Landau definition of polarization as a dipole densit…
Augmentation of the Electron Counting Rule with Ising Model
Karol Kawka, Pawel Kempisty, Konrad Sakowski +4
On semiconductor growth surfaces, surface reconstructions appear. Estimation of the reconstructed structures is essential for understanding and controlling growth phenomena. In thi…
Coulomb contribution to Shockley-Read-Hall (SRH) recombination
Konrad Sakowski, Pawel Strak, Pawel Kempisty +6
Defect-mediated nonradiative recombination, known as Shockley-Read-Hall (SRH) recombination is reformulated. The introduced model considers Coulomb attraction between charged deep…
Macrosteps dynamics and the growth of crystals and epitaxial layers
Stanislaw Krukowski, Konrad Sakowski, Paweł Strak +3
Step pattern stability of the vicinal surfaces during growth was analyzed using various surface kinetic models. It was shown that standard analysis of the vicinal surfaces provides…
Polarization doping ab initio verification of the concept charge conservation and nonlocality
Ashfaq Ahmad, Pawel Strak, Pawel Kempisty +10
In this work, we study the emergence of polarization doping in AlxGa1-xN layers with graded composition from a theoretical viewpoint. We demonstrate that the charge conservation la…
Adsorption of ammonia at GaN(0001) surface in the mixed ammonia/hydrogen ambient - a summary of ab initio data
Pawel Kempisty, Stanislaw Krukowski
Adsorption of ammonia at NH3/NH2/H covered GaN(0001) surface was analyzed using results of ab initio calculations. The whole configuration space of partially NH3/NH2/H covered GaN(…
General aspects of the vapor growth of semiconductor crystals - a study based on DFT simulations of the NH3/NH2 covered GaN(0001) surface in hydrogen ambient
Pawel Kempisty, Pawel Strak, Konrad Sakowski +1
Vapor growth of semiconductors is analyzed using recently obtained dependence of the adsorption energy on the electron charge transfer between the surface adsorbed species and the…
Energy of adsorption at semiconducting surfaces with Fermi level differently pinned -- ab initio study
Paweł Kempisty, Paweł Strak, Konrad Sakowski +1
It is shown that adsorption energy at semiconductor surfaces critically depends on the charge transfer to or from the adsorbed species. For the processes without the charge transfe…
Fermi level influence on the adsorption at semiconductor surfaces - ab initio simulations
Stanislaw Krukowski, Pawel Kempisty, Pawel Strak
Chemical adsorption of the species at semiconductor surfaces is analyzed showing the existence of the two contributions to adsorption energy: bond creation and charge transfer. It…
Foundations of ab initio simulations of electric charges and fields at semiconductor surfaces within slab models
Stanisław Krukowski, Paweł Kempisty, Paweł Strąk
Semiconductor surfaces were divided into charge categories, i.e. surface acceptor, donor and neutral ones that are suitable for simulations of their properties within a slab model.…
High efficiency UV emitters - theoretical investigation of GaN/AlN heterostructures
Pawel Strak, Pawel Kempisty, Stanislaw Krukowski
Density functional theory simulations were used to obtain physical properties of GaN/AlN system. Combination of these two compounds into multiquantum well (MQW) structure will indu…
On the nature of Surface States Stark Effect at clean GaN(0001) surface
Paweł Kempisty, Stanisław Krukowski
Recently developed model allows for simulations of electric field influence on the surface states. The results of slab simulations show considerable change of the energy of quantum…