ABSTRACT
We report on the observation of electron paramagnetic resonance of manganese and nickel trace impurities in bulk GaN crystals grown by the sublimation sandwich method. The resolved hyperfme structure due to interaction with55Mn (I= 5/2) nuclei has been observed in GaN, allowing unambiguous identification of the impurity. Manganese and nickel exist in Mn2+ (3d5) and Ni3+ (3d7) charge states with electron spin S= 5/2 and S=3/2, respectively, and occupy gallium sites in the GaN lattice. For Mn2+ we found g=1.999, A=70·10−4cm−1 and fine structure parameter |D| = 240·10−4cm−1. The EPR spectrum of Ni3+ in GaN has the characteristic anisotropy of an S = 3/2 system in a strong axial crystalline field. The effective g-factor values were found to be https://www.w3.org/1998/Math/MathML"> g ‖ ′ = 2.10 https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003063087/340656c1-20a0-4d5a-970c-83b3b7ea0fef/content/ieq0318.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> and https://www.w3.org/1998/Math/MathML"> g ⊥ ' ≅ 4.20 https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003063087/340656c1-20a0-4d5a-970c-83b3b7ea0fef/content/ieq0319.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> for a system with an effective spin https://www.w3.org/1998/Math/MathML"> S ′ =1 / 2 https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003063087/340656c1-20a0-4d5a-970c-83b3b7ea0fef/content/ieq0320.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> . An analogy was revealed between the parameters of Mn2+ and Ni3+ in GaN and ZnO crystals. The zero-phonon line at 1.047 eV seems to belong to the transition https://www.w3.org/1998/Math/MathML"> 4 T 2 ( F ) − 4 A 2 ( F ) https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003063087/340656c1-20a0-4d5a-970c-83b3b7ea0fef/content/ieq0321.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> within 3d levels of Ni3+ ion with a 3d7 electronic configuration.
