The broad and Stokes-shifted photoluminescence line in ultra-wide-band gap semiconductors has numerous potential applications starting from white light generation, nanoscale optical thermometers to quantum information readout. Here, using density functional theory with an effective U approach and hybrid functional study, we establish the correlation between self-trapped hole polaron relaxation dynamics and broadness in photoluminescence spectra of ultra-wide-band gap oxide ${\mathrm{LiGaO}}_{\text{2}}$. After electron capture, self-trapped hole undergoes large lattice relaxation and gives rise to a broad and strongly Stokes-shifted emission band peaking at 4.17 eV. The donated holes from single acceptor defects form tightly bound states and serve as deep defects. These defects also provide additional stability to bound hole polarons and produce broader luminescence bands, with peaks in the infrared to the visible range of 2.4–4.1 eV. Our findings shed light on the fundamental properties of ultra-wide-band gap semiconductor oxides and provide insights into strategies for tuning luminescence bands for future optoelectronic applications.

Close

PrevNext

View figure in article

• Defects
• Electronic structure
• Impurities in superconductors
• Polarons
• Semiconductor compounds
• Density functional calculations
• Photoluminescence