Hole g factors in GaAs quantum dots from the angular dependence of the spin fine structure

We have studied the spin fine structure of neutral and negatively charged excitons in interfacial quantum dots in GaAs quantum wells. By rotating the sample in magnetic fields up to 9 T, we have been able to study in detail the in-plane g factor for holes, which is 0.09 +/- 0.02 for the charged exciton and 0.0 +/- 0.02 for the neutral exciton in a 2 nm well.