Thermal-anneal wavelength modification of multiple-well p-n AlxGa1−x As-GaAs quantum-well lasers

Abstract

Data are presented showing that ordinary thermal annealing can be used to modify GaAs square wells into rounded Al_xGa_1−xAs quantum wells and shift the continuous 300‐K laser operation of a p‐n multiple‐well Al_xGa_1−xAs–GaAs heterostructure laser to higher energy. Transmission electron microscopy is used to show that thermal annealing at 900 °C for 10‐h changes, for example, well sizes from 85 to 105 Å and coupling barriers from 95 to 75 Å, which results in a change of laser photon energy of Δℏω∼50 meV. Bandfilling is minimal in multiple quantum‐well lasers, thus making thermal annealing a useful method to ‘‘tune’’ a continuous 300‐K quantum‐well laser to shorter wavelength as shown here. These thermal annealing experiments indicate that the Al‐Ga interdiffusion coefficient at a heterointerface is D(900)∼10⁻¹⁸ cm²/s.