MBE growth techniques for InAs-based nBn IR detectors

This manuscript describes an investigation of the effects of growth temperature on InAs epitaxial layers and InAs-based nBn detectors grown by molecular beam epitaxy (MBE). The motivation for this work is to improve the overall performance of InAs-based nBn detectors, which depends both on the bulk material quality of the individual device layers, particularly the infrared absorbing layer, as well as on the quality of the layer interfaces, particularly the interface between the absorber and barrier layers. Absorber layer bulk quality and absorber/barrier interface quality are presumably optimized by performing InAs growth at different temperatures, thus the preferred MBE growth strategy is not immediately apparent. InAs epitaxial layers of 2 μm thick are grown at several temperatures ranging from 420 to 490 °C, and are examined by differential interference contrast microscopy, atomic force microscopy, steady-state photoluminescence, and time-resolved photoluminescence measurements. Absorber layers of 2 μm...