HIGH-QUALITY ZnO LAYERS GROWN ON 6 H-SiC SUBSTRATES BY METALORGANIC CHEMICAL VAPOR DEPOSITION

The 6 h-SiC substrate has been studied for the growth of the ZnO layer. The X-ray diffraction measurement clearly showed the c-axis oriented growth of ZnO layers on SiC(0001) substrates. The X-ray rocking curve measurement diffracted a smaller full-width at half maximum of the ZnO layers grown on SiC than that of the same layers grown on the conventional Al2O3 substrate with MOCVD. A distinct free-exciton emission was dominantly observed even at RT while the donor-bound-exciton peaks were disappeared at around ~120 K. In addition, no deep-level emission was observed even at RT in the ZnO /SiC samples. These optical and crystalline properties have hardly been observed in the ZnO/Al2O3 samples grown by MOCVD. Therefore, the higher quality of the ZnO layers grown on SiC might be attributed to the smaller lattice mismatch of ~5% as well as the +c surface orientation in ZnO/SiC sample geometry. 20 refs.