GaAs three-terminal double delta-doped triangular barrier switch prepared by molecular beam epitaxy

A novel S-shaped negative differential resistance (NDR) switching device, prepared by molecular beam epitaxy (MBE), has been successfully developed in a GaAs double delta-doped triangular barrier (TB) structure. All symmetrical S-shaped NDR characteristics, either unidirectional or bidirectional bistability phenomena, are observed experimentally. The bidirectional current-voltage (I–V) characteristics exhibit a new type of NDR caused by an avalanche multiplication process in the reverse-biased base-collector region and by barrier redistribution. Under a base current injection with respect to the cathode, the device behaves as a conventional transistor with a current gain of 1.2 at room temperature. Experimentally, electrical results can be easily understood by an equivalent circuit and a proposed model. In addition, a new optoelectronic switching device is also proposed which may have the potential for bidirectional wavelength emission. On the basis of the first utilization of a double delta-doped TB structure, a conceptual understanding of such a set of results enhances our understanding of the physics of double delta-doped TB devices in general.