DYNAMIC VAPOR-PRESSURE MEASUREMENTS OF DI-TERTIARYBUTYL SULFIDE USINGAN ULTRASONIC MONITOR

Di-tertiarybutyl sulphide is an attractive precursor for the growth, u sing metal-organic vapour-phase epitaxy (MOVPE), of sulphur-based wide band-gap II-VI compounds due to its lower volatility compared to othe r more commonly used sulphur sources and likely suppression of unwante d gas-phase pre-reactions. The vapour pressure of MOVPE precursors is a key parameter and needs to be precisely known in order to control th e concentration of source materials entering the reactor. Only scatter ed and incomplete vapour pressure data exist for di-tertiarybutyl sulp hide. The concentration under dynamic conditions was measured with an Epison concentration monitor and used to predict the saturated vapour pressures. The vapour pressure equation (log(10) p = 8.559(+/- 0.082) - (2335(+/- 23)/T) was obtained and the measured vapour pressures were found to be consistently smaller than the reported literature values. The saturated vapour pressure for tertiarybutyl thiol under dynamic c onditions has also been measured and new data are reported.