Plasma-assisted MOCVD growth of GaMnN

Abstract

The growth of GaMnN thin films on c-plane sapphire substrate by plasma-assisted metalorganic chemical vapor deposition (PAMOCVD) method is reported. Cyclopentadienyl manganese tricarbonyl (Cp2MnT) was used as a source of Mn. The growth was conducted at varied growth temperature in the range of 625 to 700°C and V/III flux ratios between 440 and 1080. The growth rate and Mn incorporation into GaN highly depend on growth parameters. From the analysis of XRD spectra, it was found that the highest Mn incorporation into GaMnN which would produce single phase GaMnN (0002) was 6.4 % at growth temperature of 650°C. While at growth temperature of 700°C, the maximum of Mn incorporation into GaMnN films that would still produce single phase film were 3.2 %. The surface roughness of the films determined from AFM image results showing that high growth temperatures tend to improve the surface morphology of GaMnN. The results of magnetization measurement shows hysteresis behavior at room temperature with various values of coercivity, saturation and remnant magnetization in the range of 350-800 Oe, 20-39 emu/cm3 and 10.2–34.4 emu/cm3, respectively depend on the Mn concentration. For the films grown at 650 °C, the highest magnetic moment per Mn-atom was obtained by a sample with Mn concentration of 2.0 %, i.e. 3.1 µΒ/Mn-atom. While for the films grown at 700°C, the highest magnetic moment per Mn-atom was obtained by a sample with Mn concentration of 2.5 %, i.e. 3.7 µΒ /Mn-atom.