SPECTRAL AND ELECTRICAL CHARACTERISTICS OF Mn- AND Mn-Zr-DOPED BaGa2O4 PHOSPHORS

Dmytro Slobodzyan, Markiyan Kushlyk, Vyacheslav Vasyltsiv, Ivanna Medvid, Andriy Luchechko

Abstract


Background. BaGa2O4 is a wide-band-gap oxide with promising luminescent and electronic properties, making it a potential host for phosphor and optoelectronic materials. Controlled doping provides an effective approach for modifying its luminescence, defect structure, and charge-transport properties.  

Materials and Methods. Undoped BaGa2O4 (BGO), BGO: 0.1 mol% Mn, and BGO: 0.1 mol% Mn, 0.2 mol% Zr were synthesized by the high-temperature solid-phase method. Photoluminescence and photoluminescence excitation spectra were measured at room temperature. DC conductivity was investigated in vacuum in the temperature range of 370–490 K, while AC conductivity was measured in the frequency range of 100 Hz–50 kHz using an excitation electrical field amplitude of 5.0 V.

Results and Discussion. Undoped BGO exhibits intense broadband blue luminescence with a maximum near 410 nm, attributed to host emission centers. Mn doping shifts the emission maximum to 430-440 nm, significantly decreases the intensity, and introduces an additional excitation band at 270–340 nm, indicating the existence of an effective excitation channel associated with Mn centers. Co-doping with Zr further decreases the intensity but does not substantially change the emission spectral composition. According to the CIE 1931 analysis, the color purity decreases from 80% for BGO to 75% and 71% for Mn- and Mn-Zr-doped samples, respectively. Electrical measurements show that Mn doping increases DC conductivity by more than an order of magnitude, whereas Mn-Zr co-doping reduces the conductivity while maintaining values above those of undoped BGO. The DC activation energies remain close, ranging from 1.15 to 1.19 eV. AC conductivity exhibits frequency dispersion described by the universal Jonscher law, with the temperature dependence of the exponent s indicating changes in localized charge-transport mechanisms.

Conclusion. Mn and Mn-Zr doping effectively modify the optical and electrical properties of barium gallate through changes in localized states and defect structure. The ability to tune luminescence and charge transport highlights the potential of doped BaGa2O4 for phosphor and optoelectronic applications.

Keywords: BaGa2O4, Mn-Zr dopants, luminescence, electrical conductivity, localized states, phosphors


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References


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DOI: http://dx.doi.org/10.30970/eli.35.16

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