MOVPE-grown GaSb(100) surfaces were investigated with in situ RAS, LEED, and UPS. The in situ signals turned out to be very useful in determining suitable growth parameters and in monitoring the critical deoxidation procedure. Undoped Gasb(100) films were grown with triethylantimony and triethylgallium as precursors. Characteristic differences in the in situ signals were correlated with surface sensitive measurements after having transferred the samples with a patented procedure from the MOVPE reactor into ultrahigh vacuum chambers. p-type doping was accomplished with the precursors ditertiarybutylsilane and carbon tetrabromide, that are sustainable alternatives compared to silane and carbon tetrachloride. LEED images of the surfaces displayed a c(2 x 6) surface reconstruction. Doping levels in the range from 10(17) to 10(20) cm(-3) were observed with SIMS and Hall measurements. Characteristic RAS peaks at the E-1 and E-1 + Delta(1) interband transitions were attributed to the linear electro-optic effect and were found to increase linearly with the dopant concentration. (C) 2003 Elsevier B.V. All rights reserved.