CONFOCAL PHOTOLUMINESCENCE - A DIRECT MEASUREMENT OF SEMICONDUCTOR CARRIER TRANSPORT PARAMETERS

Using confocal microscopy a direct measurement of the minority carrier diffusion length of 5-mu-m is obtained for a 3-nm thick AlGaAs/GaAs graded-index separate confinement heterostructure. A photoluminescence spatial resolution of < 1-mu-m is obtained by translating the collection aperture of the confocal microscopy arrangement. This technique provides a method for obtaining spatial resolution in photoluminescence from semiconductor structures that is limited only by the optics rather than by carrier transport effects. This resolution is illustrated by monitoring enhanced carrier transport for a transversely graded thickness quantum well formed by metalorganic chemical vapor deposition growth over a cleaved sample edge.