Superconductivity in carrier-doped silicon carbide

We report growth and characterization of heavily boron-doped 3C-SiC and 6H-SiC and Al-doped 3C-SiC. Both 3C-SiC:B and 6H-SiC:B reveal type-I superconductivity with a critical temperature T-c = 1.5 K. On the other hand, Al-doped 3C-SiC (3C-SiC:Al) shows type-II superconductivity with T-c = 1.4 K. Both SiC:Al and SiC: B exhibit zero resistivity and diamagnetic susceptibility below T-c with effective hole-carrier concentration n higher than 10(20) cm(-3). We interpret the different superconducting behavior in carrier-doped p-type semiconductors SiC:Al, SiC:B, Si:B and C:B in terms of the different ionization energies of their acceptors.