Abstract: The disclosed light emitting semiconductor device has an n-type (or p-type) base region sandwiched by a p-type (or n-type) emitter region and a p-type (or n-type) collector region. An injecting voltage source is connected across the emittter region and base region so as to apply a constant voltage therebetween, while a control voltage source is connected across the emitter region and the collector region so as to selectively apply a reverse bias to a base-collector junction for controlling recombination of carriers injected to the base region. The control voltage source produces such non-emitting period voltage and emitting period voltage that carriers injected during the non-emitting period voltage are captured in the base region while the carriers thus captured are allowed to recombine during the emitting period voltage.

Abstract: Adjacent memory layers of a multi-layered integrated device as optically coupled, so that data written on one layer can be copied onto its adjacent layers through the optical coupling.