The effect of dopant and optical micro-cavity on the photoluminescence of Mn-doped ZnSe nanobelts

Pure and Mn-doped ZnSe nanobelts were synthesized by a convenient thermal evaporation method. Scanning electron microscopy, X-ray powder diffraction, energy dispersive X-ray spectroscopy and corresponding element mapping, and transmission electron microscope were used to examine the morphology, phase structure, crystallinity, composition, and growth direction of as-prepared nanobelts. Raman spectra were used to confirm the effective doping of Mn²⁺ into ZnSe nanobelts. Micro-photoluminescence (PL) spectra were used to investigate the emission property of as-prepared samples. A dominant trapped-state emission band is observed in single ZnSe_Mn nanobelt. However, we cannot observe the transition emission of Mn ion in this ZnSe_Mn nanobelt, which confirm that Mn powder act as poor dopant. There are weak near-bandgap emission and strong 4_T1 → 6_A1 transition emission of Mn²⁺ in single ZnSe_MnCl2 and ZnSe_Mn(CH3COO)2 nanobelt. More interesting, the 4_T1 → 6_A1 transition emission in ZnSe_Mn(CH3COO)2 nanobelt split into multi-bands. PL mapping of individual splitted sub-bands were carried out to explore the origin of multi-bands. These doped nanobelts with novel multi-bands emission can find application in frequency convertor and wavelength-tunable light emission devices.