Optical insights of indium-doped β–Ga₂O₃ nanoparticles and its luminescence mechanism

Undoped and In³⁺ doped β–Ga₂O₃ nanoparticles have been synthesized at 900 °C using polyol-mediated technique. The effect of Indium dopant on structural, morphological and photoluminescence properties of β–Ga₂O₃ nanoparticles were investigated in detail. X-ray diffraction patterns demonstrate the monoclinic crystalline structure and indium doping leads to substantial changes in the lattice parameters of β–Ga₂O₃ nanoparticles. The scanning electron microscope (SEM) images showed reduction in the particle size on doping as due to grain growth inhibition effect. Observed red shift in emission maxima and is increasing with increased In³⁺ content. Indeed, the shift changes are due to the interactions between donors and acceptors, which are identified as donor–acceptor pair recombination. To understand the red-shift phenomena, we performed time-resolved and steady-state spectroscopic studies for the doped samples. The red shift in the emission maxima of Indium-doped samples was further confirmed with the band gap measurements using absorption spectroscopy and ab initio calculation results.