A confocal photoluminescence study of metalorganic chemical vapor deposition growth on patterned GaAs substrates

New insight is provided into the properties of GaAs/AlGaAs quantum wells and associated heterostructure layers grown by metalorganic chemical vapor deposition over grooves etched into GaAs substrates, an important class of geometries for multidimensional quantum confinement. A new, noncontact, simple characterization technique, confocal photoluminescence (CPL), provides composition, thickness, and electronic quality information with ≲1 μm spatial resolution, significantly improved over the traditional diffusion length limit of photoluminescence. Room temperature CPL spectra show: AlGaAs composition variations along the groove sidewall, including large compositional fluctuations on a 1 μm scale; variations in AlGaAs composition and material quality extending several μm’s from the groove edges; and rapid variations in quantum well thickness and optical properties, particularly along high‐index growth planes.