Compositions and properties of high-conductivity nitrogen-doped p-type β-Ga2O3 films prepared by the thermal oxidation of GaN in N2O ambient

A remarkable improvement in the conductivity of grown nitrogen-doped p-type beta-Ga2O3 films was successfully achieved via the thermal oxidation of GaN in N2O ambient at 1100 degrees C. In the vacuum test environment, its room temperature Hall hole concentration is 1.64 x 1017 cm(-3), the Hall resistivity is 7.66 Omega cm, the Hall hole mobility is 4.98 cm(2) V-1 s(-1), and the acceptor ionization energy is 0.087 eV. In addition, the compositions and properties were also extensively investigated. When the oxidation temperature was raised from 900 to 1100 degrees C, the FWHM of the {(2) over bar 01}-oriented beta-Ga2O3 diffraction peak from the X-ray diffraction (XRD) pattern decreased to 0.237 degrees, confirming an improvement in the crystalline quality of the beta-Ga2O3 nanocrystal structure. From both the cross-sectional view of the field emission scanning electron microscopy (FESEM) image and the cross-sectional lamellae prepared by focused ion beam (FIB) milling, it was observed that the generated beta-Ga2O3 film transformed into a two-layer morphology when oxidized at 1100 degrees C. The top layer is a rather loose film composed of nanorods, and the selected area electron diffraction (SAED) pattern of a nanorod confirmed it as high-quality ((6) over bar 03)-dominated monocrystal beta-Ga2O3. The second layer is a comparatively compact beta-Ga2O3 film. This approach to the efficient growth of p-type beta-Ga2O3 can broaden the applicability of these two-layered structures. The randomly distributed monocrystal nanorods on the top layer are an appropriate candidate for the photocatalyst, while the relatively more compact second layer with high p-type conductivity can be employed in high-performance solar-blind UV photodetectors or high-power electronic devices. (C) 2022 The Author(s). Published by Elsevier B.V.

Automated summary

A remarkable improvement in the conductivity and crystalline quality of grown nitrogen-doped p-type beta-Ga2O3 films was achieved by thermal oxidation of GaN in N2O ambient. The resulting two-layer structure, with a top layer composed of nanorods and a bottom compact layer, can be applied to photocatalysts and high-performance photodetectors or electronic devices.