4.2 Optoelectronics: QD Lasers Employing Full Three-Dimensional Active Region Carrier Confinement
Abstract
The objectives of this proposal are to (1) Develop in-situ etching and sulfide/selenium based techniques to passivate surface states in etched quantum dots (QDs), and (2) Develop improved performance lasers employing the nano-patterned QD active regions on GaAs substrates. The approach to be pursued in the 3 year proposed work will build on the proposer s recent success in fabricating QD lasers on GaAs substrates and address the remaining issues through a closely coupled materials and device development effort to include the systematic study of the impact of in-situ CBr4 etching and other passivation methods on the photoluminescence (i.e. radiative efficiency) and QD laser device performance. Feedback from device performance will be a key measure of how process improvements impact QD radiative efficiency. One method to minimize process induced surface damage; investigation of the use of an ultra-thin SiO2 mask, allowing wet etching to be utilized to transfer the nano-pattern from di-block co-polymer to dielectric. Non-aqueous sulfide passivation is another method to be investigated. The following tasks summarize the approaches to be taken: 1. Surface passivation studies will be undertaken. QD materials on GaAs substrates will be utilized as a passivation testbed. Single layer QD active regions will be formed and incorporated into lasers for performance evaluation and feedback for the passivation techniques. 2. Carrier injection into the QD active regions will be studied through device characterization of injection efficiency and temperature sensitivity. Improved carrier injection methods, such as tunneling injection, will be evaluated. Laser heterostructure optimization for higher efficiency will be undertaken. 3. Fabrication of double-stack QD active regions will be studied. Optimization of dielectric mask and selective growth conditions will be used to determine appropriate procedures for stacking the QDs. Structural analysis will be carried out in collaboration with The Aerospace Corporation. Device implementation will provide feedback on the optical gain of such devices.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2017
- Source ID
- W911NF1610298
Entities
People
- L. J. Mawst
Organizations
- Army Contracting Command
- United States Army
- University of Wisconsin–Madison