Very narrow graded-barrier single quantum well lasers grown by metalorganic chemical vapor deposition

Abstract

Graded-barrier GaAs-GaAlAs single quantum well lasers have been fabricated, utilizing the graded-index separate confinement heterostructure to confine carriers and optical field. Very low threshold current densities have been observed down to a well size of 75 Å. The lowest threshold current density observed is 240 A/cm2 for a 100-Å heavily doped quantum well laser. This experimental value agrees very well with the calculated threshold current density obtained from detailed band calculation and is attributed to the enhanced gain-current characteristic in these quantum well structures.