Efficient temperature sensing using photoluminescence of Er/Ybimplanted GaN thin films

tThe luminescence characteristics of GaN films implanted with Er at low doses were evaluated. The defect-related yellow luminescence (YL) and green luminescence (GL) bands observed under direct excitationwith 488 nm were attributed to the transitions via different charge levels of the same defect. The quench-ing behavior of the luminescence intensity either with the temperature or concentration variation can beattributed to nonradiative energy transfer (ET) and/or charge transfer by trapping impurities. The tem-perature dependence of the YL band allowed us to identify the defect responsible for this emission. Thebest candidate for this defect was found to be a nitrogen-vacancy. A GaN sample co-doped with Er3+andYb3+ions was prepared, and its optical properties were analyzed. The incorporation of Yb3+improved thePL emission intensity in the visible region. This feature results from the efficient ET processes betweenthese two doping ions. The color coordinate analysis indicates that Er3+/Yb3+co-doped GaN semiconduc-tor emits light with color in the white-light region. To investigate the temperature sensing applicationof the synthesized co-doped semiconductor, the temperature-sensing performance was evaluated usingthe fluorescence intensity ratio technique in the temperature range 200–300K. The significant temper-ature sensitivity indicates its potential as a temperature sensing probe. The maximum sensitivity was15 × 10−4K−1at 200 K.