Observation by resonant tunneling of high-energy states in GaAs-Ga1−xAlxAs quantum wells

Abstract

The current-voltage characteristics of ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Al}}_{\mathrm{x}}$As-GaAs-${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Al}}_{\mathrm{x}}$ As double-barrier devices show, in addition to resonant tunneling via quasibound Γ states, well-defined structures corresponding to energies higher than the barrier height. These new features are interpreted as resonant tunneling through confined states in ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Al}}_{\mathrm{x}}$As, at the X point of the Brillouin zone.