A study of the photodissociation dynamics of dimethylzinc and the implications for the growth of zinc selenide films

Abstract

The dynamics of the ArF photodissociation of DMZn (dimethylzinc) have been studied. The implications of the results for the growth of ZnSe thin films are discussed. Time-resolved absorption profiles of ground state Zn and methyl radicals have been acquired using a plasma emission source. Time-resolved fluorescence from excited CH radicals has also been studied. The results indicate that the Zn concentration remains constant after the dissociating ArF pulse, indicating the system is a good source for free Zn atoms. The CH$\sb3$ radicals that are created recombine to form ethane, and simulations of the kinetics indicate that the concentration of methyl radicals reaching the substrate is insignificant. There was no indication of monomethylzinc formation. The CH radical is likely to combine with H$\sb2$ to form CH$\sb3$ within several microseconds. Thus the major sources for carbon contamination in the growth process (CH$\sb3$, MMZn, CH) are unlikely to reach the substrate.