GA-BOUND EXCITONS IN 3C-SIC, 4H-SIC, AND 6H-SIC

We report a photoluminescence (PL) study from p-type gallium-doped SiC epilayers, which reveals a PL spectrum constituted of a set of sharp lines and interpreted as excitons bound to the Ga acceptor. The PL spe ctrum consists of several zero-phonon lines, which are very close to o r superimposed on the nitrogen-bound excitons in the 4H- and 6H-SiC. T he intensity of the PL spectrum depends on the Ga concentration introd uced during the growth of the epilayers. The applicability of the Hayn es rule is shown for the accepters in SiC. A comparison with the alumi num-bound exciton is also presented.