Dislocation free strained InGaAlAs-MQW growth over an InGaAsP/InP grating

We grew a strained-InGaAlAs multiple quantum well (MQW) by low-pressure MOVPE over an InGaAsP grating on InP to fabricate an InGaAlAs-distributed-feedback (DFB) laser diode (LD). InP was overgrown on the grating in PH/sub 3/ ambient. We found that temperature, growth rate, and PH/sub 3/, partial pressure in the InP overgrowth process are the key parameters in growing dislocation-free epitaxial layers. By adjusting these parameters, we successfully grew a dislocation-free strained InGaAlAs MQW over a grating.