A novel multi-quantum well device called a Multi-Quantum-Well Injection-Mode Device (MQW-IMD) is proposed as the basic building block for simple, pulse-mode, analog electronic circuits to implement elementary neural signal processing functions. The device consists of alternating n + doped quantum wells and undoped barrier layers forming a multi-quantum well structure which is placed between an n + cathode and p + anode. This structure gives rise to an s-shaped current-voltage characteristic in forward bias where switching to the high conductance state is produced by impact ionization over the conduction band edge of electrons bound in the quantum wells. When the device is operated in simple circuits with a capacitive load, it yields a pulse-mode output which simulates a number of important characteristics of the biological neuron. As an example, the device's design and operation in the GaAs AlGaAs materials system is described and demonstrated. The device's operation is shown to be feasible at low voltage and power with operation possible at room temperature.