EXCITATION-INTENSITY-DEPENDENT PHOTOLUMINESCENCE IN SEMICONDUCTOR QUANTUM-WELLS DUE TO INTERNAL ELECTRIC-FIELDS

Low-temperature photoluminescence (PL) has been studied in several III -V single-quantum-well (SQW) samples. We have observed shifts of the P L peak energy as a function of the excitation intensity which, we show , are due to the quantum confined Stark effect (QCSE) caused by the in ternal electric field at the surface and/or heterointerfaces in the sa mples. The experimentally measured PL peak shifts in InxGa1-xAs/GaAs a nd AlxGa1-xAs/GaAs SQW's are compared with calculations based on the Q CSE and excellent agreement is found. The magnitude of the internal fi eld determined from the PL analysis coincides with the value for the e lectric field obtained from photoreflectance measurements on the same samples, at the same temperatures.