Spatial distribution of the electronic wave function of the shallow boron acceptor in 4H- and 6H-SiC

A high-frequency (95 GHz) pulsed electron paramagnetic resonance and electr on-nuclear-double-resonance study has been carried out on the shallow boron acceptor:in C-13-enriched 4H-SiC and 6H-SiC. From the hyperfine interactio n of the unpaired electron spin with the C-13 (I=1/2) nuclei the spatial di stribution of the electronic wave function has been established. It is foun d that there are subtle differences in the degree of localization of this w ave function between the different sites (two quasicubic and one hexagonal) in the two polytypes 4H-SiC and 6H-SiC, though only for the two quasicubic sites a complete study of the wave function could be made. In particular i t is found that,the spatial distribution is highly anisotropic. This anisot ropy can be rationalized by considering the anisotropy of the hole mass, i. e., by assuming that effective-mass theory is (partly) valid in describing the remote part of the spatial distribution of the electronic wave function . [S0163-1829(99)16135-6].