Growth and characterization of FexMn1-xIn2Se4 (0 x 1) single crystals

Single crystals of Mn1-xFexIn2Se4 with 0 <= x <= 1.0 were grown by chemical vapor transport technique using I-2 as transporting agent. The resulting crystals appeared as brilliant black plates. X-ray powder diffraction data could be indexed following the hexagonal structure with space group R3 ($) over barm for the low Fe concentration samples, while the high concentration sample is associated to the space group P6(3)mc. Both polytypes have similar parameters, however the c parameter reduces as the Fe concentration increases, therefore the number of anion slabs decreases. The characterization of the crystals was based on morphological observations and optical absorption as a function of temperature. The obtained energy gap for the samples at different Fe concentrations suggested that they behave as direct energy gap semiconductors.