LIGHT-EMISSION FROM ZERO-DIMENSIONAL EXCITONS - PHOTOLUMINESCENCE FROM QUANTUM WELLS IN STRONG MAGNETIC-FIELDS

The authors report the spontaneous light emission from 'zero-dimensional exciton states' in GaAs/GaAlAs quantum wells under a high magnetic field at 80 K. The formation of such fully quantized states is evidenced by observing the wavelength shift DELTA lambda of the spontaneous emission peak as well as the narrowing of the spectrum width as the magnetic field is raised up to 15 T. The observed shift DELTA lambda is shown to be well explained by the theory in which the high magnetic field effect on two-dimensional hydrogenic exciton is taken into account. The formation of such a novel state is further evidenced by the strong anisotropy of the photoluminescence spectrum, which depends on the direction of the magnetic field.