MnSe - Molecular Beam Epitaxy Growth and Optical Characterisation

J. Kucharek, R. Bożek, W. Pacuski Institute of Experimental Physics, Faculty of Physics, University of Warsaw, L. Pasteura 5, PL-02093 Warszawa, Poland

Full Text PDF

Here, we report on the optical properties of manganese selenide (MnSe) layers grown by molecular beam epitaxy. We compare MnSe film growths on c-plane Al2O3 in various conditions. Samples were analyzed in situ using reflection high energy electron diffraction. This technique confirmed that in specific conditions growth of crystals well oriented to the substrate is possible and the surface of such crystals became flat after tens of nm, with typical grain size dependent on growth time. Further we studied samples using room temperature optical spectroscopy. Intensity of broad peak observed in photoluminescence spectra is strong for samples with large MnSe crystallites and very weak for samples with small crystallites. Origin of this peak is attributed to Mn2+ d-d transitions strongly hybridised with Se shells. Thanks to the transparency of Al2O3, transmittance measurements have been performed on obtained layers, revealing a broad absorption band in blue spectral range, which explains the yellow color of MnSe layers. Properties observed in transmittance and the Raman scattering - large band gap and the Raman lines close to 250 cm-1 are in agreement with the data reported for the most stable polymorph of MnSe - rocksalt structure (alpha-MnSe).

DOI:10.12693/APhysPolA.136.598 topics: MnSe crystals, molecular beam epitaxy, Raman scattering, photoluminescence