Device characteristics of (AlGa)As multiquantum-well heterostructure lasers grown by molecular beam epitaxy

A study has been made on the device characteristics of multiquantum well (MQW) lasers grown by molecular beam epitaxy. These wafers have different numbers of wells and different well and barrier thicknesses. The results show that averaged threshold current densities Jth as low as the lowest Jth (800 A/cm2) obtained for standard double-heterostructure lasers with approximately the same AlAs composition in the cladding layers were obtained in spite of the reduced optical confinement factor Γ and the increased number of interfaces. Significant beam width reduction in the direction perpendicular to the jucntion plane was obtained. Half-power full-width as narrow as 15° was measured for some MQW wafers. For some MQW wafers the lasers fabricated generally have a characteristic temperature T0≳215 °C in the temperature range of 10–130 °C. The present study also shows that the device characteristics of the MQW lasers depend quite significantly on the detailed designs of the multilayer structure that composes the active region.