Quantum Dash Intermixing
We investigate the intermixing effect in InAs/InAlGaAs quantum-dash-in-well structures grown on InP substrate. Both impurity-free vacancy disordering (IFVD) via dielectric cap annealing, and impurity-induced disordering (IID) using nitrogen ion-implantation techniques have been employed to spatially control the group-III intermixing in the quantum-dash (Qdash) system. Differential bandgap shifts of up to 80 nm and 112 nm have been observed from the IFVD and IID processes, respectively. Compared to the control (nonintermixed) lasers, the light-current characteristics for the 125 nm wavelength shifted Qdash lasers are not significantly changed, suggesting that the quality of the intermixed material is well preserved. The intermixed lasers exhibit a narrower linewidth as compared to the as-grown laser due to the improved dash homogeneity. The integrity of the material is retained after intermixing, suggesting the potential application for the planar integration of multiple active/passive Qdash-based devices on a single InP chip.