DECOMPOSITION OF ALLYLSELENIUM SOURCES IN THE METALORGANIC CHEMICAL VAPOR-DEPOSITION OF ZNSE

The gas-phase decomposition of methylallyl selenide (MASe) and diallyl selenide (DASe) was studied in a molecular beam mass spectrometric system under conditions used for the metalorganic chemical vapor deposition of zinc selenide (ZnSe). Consistent with reported growth results, the decomposition temperature of DASe was determined to be about 60-degrees-C lower than that of MASe. Pyrolysis experiments carried out in H-2 and He carrier gases showed that allyl selenides decompose by a combination of homolysis and an intramolecular rearrangement pathway, with 1,5-hexadiene and propene being the major hydrocarbon products. By comparison, methylallyl telluride (MATe) was found to decompose almost exclusively by homolysis. Selenoaldehyde products generated by the rearrangement mechanism are concluded to be the source of carbon incorporation into ZnSe films grown using allyl Se sources.