Impact of Erbium (Er) doping in structural, optical and electrical properties of Ga2O3 nanostructures/Si heterojunctions

In the current study, we report the growth of rare earth Er-doped Ga2O3 nanostructures on Ga2O3-seeded Si substrate by employing chemical bath deposition (CBD) and RF magnetron sputtering techniques. A thin layer (similar to 50 nm) of Ga2O3 is deposited on p-Si substrate with the optimize deposition temperature and Ar:O-2 flow rate to create a favourable template for growing high quality nanostructures on it. After growing the Er-doped Ga2O3 nanostructures, thermal annealing is performed at 800 degrees C to achieve thermodynamically stable fl-phase of Ga2O3. The effect of Er doping on structural, optical and luminescence properties of Ga2O3 nanostructures has been successfully investigated by employing FEGSEM, XRD, UV-VIS and PL. XRD studies confirms the polycrystalline beta-phase monoclinic structure of Ga2O3 for both undoped and Er-doped nanostructures with dominant <-111> plane. Top view images of FEGSEM depict the large area growth of rod/wire like structures of Ga2O3 on thin Ga2O3 deposited Si substrate and confirm the formation of heterojunction between GGa(2)O(3) and Si. Deconvoluted PL spectra shows two broad peaks within the wavelength range of 260 nm to 460 nm, which are associated with near band emission and three different types of oxygen vacancies present in beta-Ga2O3, respectively. The change in optical absorbance and corresponding energy band gap of undoped and Er-doped nanostructures are analysed in detail by using UV-VIS spectroscopy and such energy bandgap values lie with the range of 4.4 eV-4.7 eV. Finally, current-voltage characteristics of undoped and Er-doped Ga2O3/Si heterojunction has been studied and such heterojunctions can be a potential candidate for the fabrication of several optoelectronic devices as well as high power applications.