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Item Effect of post-deposition annealing ambient on Gallium Oxide (Ga2O3) films(SPIE, 2022) Mishra, M.; Saha, R.; Bhowmick, S.; Pandey, S.K.; Chakrabarti, S.Gallium Oxide (Ga2O3) is an emerging wideband semiconductor which can be utilize in solar-blind photodetector and high power electronics application. Having a large bandgap and high breakdown field makes Ga2O3 material suitable for these device applications. However, the physical and the optical properties of Ga2O3 can be tailored by changing the annealing ambient and temperature, and understanding how the annealing atmosphere can affect these properties is crucial for designing a next generation optoelectronic devices. Moreover, the presence of defects and impurities can also affect the device parameters. Thus, in this work, we have investigated the influence of post deposition annealing atmosphere on the morphological, structural, and optical properties of Ga2O3 films. The prepared samples were further went through thermal annealing at 800℃ for 30 mins in Nitrogen (N2), and Oxygen (O2) ambient to achieve β-phase of Ga2O3. The structural properties of all the samples were studied by Atomic force microscopy, and X-ray diffraction while the optical properties were studies by UV-Visible, and photoluminescence spectroscopy. We have found monoclinic β-phase in the polycrystalline annealed Ga2O3 samples. The optical band gap of films were increased after annealing and highest band gap is obtained to 5.44eV in N2 annealed sample as compared to as-deposited sample (4.56eV). A broad photoluminescence spectrum ranged from 350 to 480 nm was observed, which further deconvoluted in three peaks at around 378 nm, 399 nm, and 422 nm in as-deposited sample. The same peaks with broad photoluminescence spectrum was found to be blue shifted for annealed samples as compared to the as-deposited. This study will open a new direction in future deep-UV photodetector fabrication. © 2022 SPIE.Item Unfolding the conductivity reversal n- to p-type in phosphorus-doped ZnO thin films by spin-on dopant (SOD) process(Institute of Physics, 2022) Mishra, M.; Saha, R.; Bhowmick, S.; Pandey, S.K.; Chakrabarti, S.Phosphorus doping induced p-type doping in ZnO thin films based on spin-on dopant (SOD) process is reported in this article. Owing to the reduced dependence on the conventional amenities for diffusion/ion-implantation doping, the SOD process provides a simple and cheap doping method. The effect of SOD process temperature on conductivity ZnO thin films is investigated by altering the temperature from 700°C to 1000°C. Systematic field emission scanning electron microscopy analysis demonstrates the impact of doping temperature on the morphological properties of SOD. The x-ray diffraction measurements reveal that the p-type ZnO thin films had (002) preferred crystal orientation. At the same time, x-ray photoelectron spectroscopy validated the formation of the PZn-2VZn complex, which was responsible for the acceptor behaviour of films. Moreover, the photoluminescence spectra tracked down that the origin of 3.35 and 3.31 eV emission peaks is due to the acceptor bound exciton and free-electron to acceptor level transitions, respectively. Finally, an elevated hole concentration of 2.09 × 1016 cm-3 is achieved with a resistivity of 1.14 ω-cm at 800°C doping temperature. However, the film doped at 900°C and 1000°C showed n-type behaviour due to the generation of high concentration donor defects. Here, we successfully demonstrate that the SOD process has great potential to produce high-quality p-type ZnO thin films suitable for optoelectronic devices applications. © 2022 IOP Publishing Ltd.