Environmental degradation of Al_xGa_1-xAs-GaAs quantum-well heterostructures

Data describing the deterioration of Al_xGa_{1 -x}As-GaAs heterostructures in long-term exposure (2-12 years) to normal room environmental conditions (∼20-25 °C, varying humidity) are presented. Optical microscopy, scanning electron microscopy, transmission electron microscopy, and electron dispersion x-ray spectroscopy are used to examine Al_xGa_1-xAs-GaAs quantum-well heterostructure material that has hydrolyzed at cleaved edges, cracks, and fissures, and at pinholes in cap layers. The hydrolysis is found to be significant for thicker (>0.1 μm) Al_xGa_{1 -x}As layers of higher composition (x>0.85).