Photoemission oscillations have been observed during the growth of InAs and AlSb on (001) GaAs substrates. The ability to observe photoemission oscillations is dependent on the growth conditions in a manner similar to reflection high-energy electron diffraction oscillations. Consequently, the mechanism responsible for photoemission oscillations is believed to be related to fluctuations in surface step density during deposition. We have used the photoemission oscillation technique to measure the AlSb barrier thicknesses during the growth of InAs/AlSb resonant tunneling diodes. Measured peak current densities are clearly better correlated with barrier thicknesses measured by photoemission oscillations than by barrier thicknesses assumed by time-based "dead reckoning." Calculations of current/voltage characteristics of the resonant tunneling devices indicate that a substantial amount of As is incorporated in the barrier layer as a result of the growth conditions selected.