High lateral density (∼1011 cm-2) and well-aligned quantum dot (QD) structures are self-formed in (GaAs)2(InAs)
n
short period superlattices grown on InP(411) substrates by gas source molecular beam epitaxy. Light emitting diodes with these QDs as an active layer were fabricated. However, the light output power showed saturation for the driving current of over 100 mA. To overcome this problem, an InAlAs layer was inserted between QD active layer and p-type cladding layer as a current blocking layer. As a result, no saturation of output power was obtained up to 200 mA. Furthermore, pulsed current injection laser operation was realized for these layer structures.