ELFT HÍRADÓ

[Szeminárium koordinátor <sem-admin AT wigner.hun-ren.hu>]

PhD Preliminary DefenseBezerra Morais, SarahHUN-REN Wigner RCP SZFIStudy of 
solid-state photon emitters in SiCThursday, 28 May 2026, 14:00, KFKI Campus, 
Bldg. 1, 2nd floor, Conference RoomSupervisor: Dávid BekeIn this doctoral 
thesis, I investigate the controlled chemical synthesis of photon-emitting 
point defects—commonly known as color centers—in silicon carbide (SiC), with 
the aim of providing an alternative to irradiation-based methods using 
scalable thermal and mechanochemical approaches. The optically active defects 
I focused on are the negatively charged silicon vacancy and the neutral 
divacancy, which offer near-infrared emission and long spin coherence times 
relevant to quantum sensing and communication applications. I generated 
colour centres through combustion-assisted thermal synthesis from silicon and 
carbon precursors, using induction and tube furnaces to systematically vary 
heating rate, temperature, and dwell time. I identified a critical synthesis 
window between 1050–1150 °C, within which defect-related photoluminescence 
signatures are preserved. I found that rapid heating favours non-equilibrium 
conditions conducive to vacancy formation, while slow heating promotes 
structural relaxation and reduces defect density. I achieved silicon vacancy 
densities exceeding 10¹⁷ spins/cm³ — comparable to irradiation-based 
benchmarks. Through multivariate statistical analysis, I further established 
that hexagonal polytype fraction and stacking-fault density are the dominant 
structural predictors of optically active defect concentration, providing a 
new framework for defect engineering in wide-bandgap 
semiconductors. Minden érdeklődőt szívesen látunk! - Everyone is welcome 
to attend.Tamás Pusztaisem-admin AT wigner.hun-ren.hu