Selective growth and chracterization of InGaAs Quantum Dots on patterned InP substrates utilizaing a diblock copolymer template

To realize the theoretical advantages of Quantum Dots (QDs) as the active region for diode lasers, the selective growth of QDs on patterned substrates were investigated. The substrate nanopatterning and QD formation was realized by diblock copolymers combined with selective MOCVD growth. Using a CF₄ reactive ion etch (RIE) and a sacrificial SiN_x mask, diblock copolymer nanopattern was transferred to InGaAs QDs on top of prepared InGaAsP / InP substrates and then QDs were grown selective ly by MOCVD. Since growth temperature of patterned QDs is free from QD formation mechanism, unlike self-assembled QDs, two samples were grown at relatively higher temperatures (550 degC and 630 degC) and a significant improvement in photoluminescence (PL) was observed from the sample grown at higher temperature.