Effects of rapid thermal annealing and SiO2 encapsulation on GaInAs/AlInAs heterostructures

Substantial blue shifts in the transition energies of GaInAs/AlInAs single quantum wells were observed due to localized SiO2 capping and rapid thermal annealing at temperatures between 750 and 900 °C. In contrast to previously reported results, regions capped with SiO2 exhibited blue shifts up to 74 meV while regions with no SiO2 showed minimal shifting. With this band‐gap change, a lateral index change of approximately −0.6% is anticipated making this process suitable for index‐guided lasers. Samples also exhibited up to 15‐fold increases in PL efficiencies due to the annealing process. The dependence of energy shifts and PL efficiencies is studied by measuring room‐temperature and low‐temperature photoluminescence.