NEW ALLYL SELENIDE AND TRIALKYLPHOSPHINE SELENIDE PRECURSORS FOR METALORGANIC VAPOR-PHASE EPITAXY OF ZNSE

New allyl selenide and trialkylphosphine selenide reagents; specifical ly, t-butylallyl selenide (tBASe) and tripropylphosphine selenide, are described for the metalorganic vapor phase epitaxy (MOVPE) of ZnSe. T he gas-phase chemistry of allyl selenide precursors is discussed, with emphasis on reactions leading to carbon incorporation. Secondary ion mass spectrometry shows a negligible carbon incorporation in ZnSe film s grown from tBASe even at high [VI]/[II] ratios, in contrast to a car bon concentration of 10(21) cm(-3) in ZnSe films grown from diallyl se lenide and methyl allyl selenide. The low carbon concentration is attr ibuted to the t-butyl group precluding internal rearrangement reaction s responsible for carbon incorporation. Low temperature growth and sho rt residence times are critical to minimizing alkyl group redistributi on reactions that lead to formation of potential carbon precursors; sp ecifically, diallyl selenide. Good surface morphology on (001) GaAs an d photoluminescene spectra with sharp near-band-edge excitonic emissio n is reported. The need to reduce hydrogen incorporation to improve ni trogen doping characteristics motivates the development of alternative Se precursors circumventing formation of Se-H moieties. Phosphine sel enides are proposed as a promising family of reagents and results are presented for growth of ZnSe with tripropylphosphine selenide and dime thylzinc.