Precise control of conduction type of higher manganese silicide single crystals via vanadium and iron co-substitution

The feasibility of using higher manganese silicide MnSi γ ~1.73 with a low carrier concentration ( N ) for near-infrared (NIR) absorption applications was investigated. Vanadium (V) and iron (Fe) co-substituted MnSi γ single crystals, (Mn 0.99- x V 0.01 Fe x )Si γ , were synthesized using a melting method. V doping diminished the MnSi striations in the single crystals, whereas Fe substitution inverted the conduction-type of the co-substituted MnSi γ single crystals from p -type to n -type. These findings are corroborated by the Hall coefficient measurements. The variation in the valence electron counts (VEC) confirmed that the pn transition occurred at VEC ≈ 14.007, consistent with the 14-electron rule. At the pn transition, the lowest N ≈ 7.3(4)×10 16 cm -3 was obtained, resulting in the formation of a sufficiently thick depletion layer. These results indicate that (Mn 0.99- x V 0.01 Fe x )Si γ single crystals are promising NIR absorption candidates. • ・ (Mn, V, Fe)Si γ single crystals suitable to absorb near-infrared light were obtained by melt-growth method. • ・V prohibited emergence of the MnSi striations. • ・Fe changed the conduction type of (Mn, V, Fe)Si γ single crystals from p-type to n-type around VEC = 14.007. • ・The lowest carrier density N = 7.3(4)×10 16 cm -3 was achieved to form a sufficiently thick depletion layer.