Bound to continuum superlattice miniband long wavelength GaAs/AlxGa1−xAs photoconductors

Abstract

We have measured and theoretically analyzed the optical absorption and hot electron transport physics of a new long wavelength (λ=5–9 μm) infrared miniband photoconductor based on a GaAs/Al_xGa_1−x superlattice. The optical absorption photoexcites an electron from the lowest miniband below the barriers to the excited state which is designed to be above the top of the barriers. This bound to continuum absorption leads to more than an order of magnitude improvement in electron transport and detector performance, compared with previous bound state miniband photoconductors.