Quantum Dots for Future Nanophotonic Devices: Lateral Ordering, Position, and Number Control

After the general aspects of InAs/InP (100) quantum dots (QDs) regarding the formation of QDs versus quantum dashes, wavelength tuning from telecom to mid-infrared region, and device applications, we discuss our recent progress on the lateral ordering, position, and number control of QDs. Single-layer and stacked linear InAs QD arrays are formed by self-organized anisotropic strain engineering of an InAs/InGaAsP superlattice template on InP (100) with emission wavelength at room temperature in the important 1.55-$\mu \hbox{m}$ telecom wavelength region. Guided and directed self-organized anisotropic strain engineering is demonstrated on shallow- and deep-patterned GaAs (311)B for the formation of complex InGaAs QD arrays and absolute QD position control. The lateral position, distribution, and number control of InAs QDs, down to a single QD, are demonstrated on truncated InP (100) pyramids by selective-area growth with sharp emission at 1.55 $\mu\hbox{m}$. Submicrometer-scale active–passive integration is established by the lateral regrowth of InP around the pyramids for planarization. Such control over QD formation is the key to future quantum functional nanophotonic devices and integrated circuits operating at the single- and multiple-electron and photon level with controlled interactions.