EPR Studies on Defects and Conduction Band electrons in Ga₂O₃

                                                     Interest of EPR spectroscopy

• It gives access to the chemical nature of the defect  (CHF interaction)
• The electronic configuration (spin state) allows the determination of the charge state
• The g-tensor anisotropy reveals the local point symmetry and thus the lattice site
• Photoinduced EPR can determine the level position in the gap
• EPR is quantitative / absolute defect concentrations

Examples of previous studies

• Ga vacancy defects
• Neutral Shallow donor  centers
• Transition metals

  Polytypes studied: a, b, ε thin films and bulk Ga2O3 crystals

  Transition metals                                                                                                                                                                                                                                                                                

  Fe3+ ,Mn2+on Ga1 and Ga2 lattice sites

  Cr3+ on Ga2; Ir4+; Ti3+; Gd3+

  Shallow donors

  Si, SnGa1

  Deep acceptors

  Zn°Ga2, Mg°Ga

    Intrinsic defects/radiation induced defects

  VGa2-   S=1/2  /  S=1

                                                                         

  Free electrons

  T>100K

  Self trapped holes

  T<100K