Effect of spacer layer thickness on tunneling characteristics in asymmetric AlAs/GaAs/AlAs double barrier structures

Abstract

We present a first-time study of the effects of variable thickness undoped spacer layers of asymmetric AlAs/GaAs/AlAs double barrier structures on resonant tunneling current-voltage ( I- V) characteristics. Although tunneling characteristics are only observed in the negative voltage sweep of the I- V curve, these structures do exhibit increased current density ( j p) with increased spacer layer thickness ( L sp) until a threshold thickness of L sp > 10 nm is reached. Above L sp = 10 nm, current density decreases. A modified asymmetric double barrier structure with reduced overall emitter-collector layer thickness was also examined. The latter provided insight into sample optimization as more prominent resonant tunneling characteristics were observed in comparison to the original structures.