Effect of metal organic vapor phase epitaxy growth conditions on emission wavelength stability of 1.55μm quantum dot lasers

Abstract

InAs quantum dots (QDs) on InP were implemented as active layers in laser structures completely grown by metal organic vapor phase epitaxy (MOVPE). In laser structures due to growth of the upper InP cladding layers onto the QDs, a marked blueshift of the emission wavelength and a simultaneous degradation of photoluminescence intensity were observed. This behavior was systematically investigated using thermal treatment to simulate the growth of the upper cladding layer. Using an adequate growth procedure emission behavior was achieved that has proven to be fairly insensitive to over-/regrowth steps. Broad-area 1.55μm emitting laser devices were fabricated by incorporating seven QD layers in an all-MOVPE grown structure. Transparency current densities per dot layer of 80Acm−2 were achieved which is close to values of multiple quantum well lasers processed in the same way.