Nanopatterned Quantum Dot Lasers for High Speed, High Efficiency, Operation

Quantum dot QD active regions hold potential for realizing extremely high performance semiconductor diode lasers. Unfortunately, these unique features of ideal QD active layers have not been fully realized to date. The most successful approach to date of forming QD s is selfassembly under the Stranski Krastanow SK growth mode. However, this approach results in a relatively large distribution of QD sizes, leading to significant inhomogeneous broadening of the spectral gain. SK QDs inherently form on top of a two-dimensional wetting layer , leading to weak electron and hole confinement to the QD, which results in low gain saturation. Here, we have investigated the use of dense nanoscale diblock copolymer lithography-based nanofabrication and selective quantum dot growth using metalorganic chemical vapor deposition MOCVD. These methods allowed us to realize quantum dot active regions in which the injected carriers exhibit full threedimensional nano-scale confinement and elimination of the wetting layer states. The objectives of this project were to develop lasers employing the nano-patterned QD active regions and investigate the characteristics of these novel active regions.