COMPARISON OF THE QUANTUM-CONFINED STARK-EFFECT FOR (100)A-ORIENTED AND (311)A-ORIENTED GAAS/ALGAAS QUANTUM-WELLS USING ELECTROREFLECTANCE SPECTROSCOPY

The excitonic subband transitions of (100)- and (311)A-oriented GaAs/AlGaAs single quantum wells (SQW's) are investigated using electroreflectance spectroscopy. The strong Franz-Keldysh-Oscillations arising from the undoped AlGaAs barrier layers are analyzed to determine the field strength within the SQW's directly from the measurements with high accuracy. Both, the orientation-dependent splitting between the first heavy and light hole subbands and their field-induced shifts are compared with the results of k . p calculations. Best agreement between experiment and theory is obtained for a set of Luttinger parameters corresponding to heavy and light hole masses of 0.55m(0) and 0.084m(0), respectively, along the [311] direction. (C) 1995 Academic Press Limited