Laser data (77 and 300 K) are presented on an AlxGa1−xAs‐AlAs‐GaAs quantum‐well heterostructure (QWH) grown by metalorganic‐chemical vapor deposition with an active region consisting of 13 AlAs barrier layers of sizeLB∼10 A˚ and 12 GaAs quantum wells of sizeLz∼50 A˚. This QWH, which is free of alloy disorder and clustering (Al‐Ga clusters) in the active region, emits on the confined particle transitions and not at the lower energies characteristic of QWH’s with AlxGa1−xAs barrier layers (and Al‐Ga clusters).