Fabrication of optical sources using InGaAs quantum dots grown by atomic layer epitaxy

We report that the characteristics and the device applications of InGaAs quantum dots (QD's) grown by using the atomic layer epitaxy (ALE) technique. The measured average diameter and height of the QD's are about 45 nm and 7 nm, respectively. The typical density of QD's is 1.4 × 10¹⁰/cm ² for a single layer. Optical sources, like laser diodes (LD's) and superluminescent diodes (SLD's), are fabricated on epi-structures with an active medium consisting of InGaAs QD's. In the case of LD's, the lasing wavelength is about 1.02 μm, which reflects lasing at high-energy states. The internal quantum efficiency and the internal loss is about 66 % and 45 cm^-1, respectively, In the case of SLD's. the output power is about 0.9 W, and the spectral bandwidth is 93 nm. Procedures to further improve device performances are also discussed.