ELECTROLUMINESCENCE STUDY OF RESONANT-TUNNELING IN GAAS-ALAS SUPERLATTICES

We have studied the electroluminescence (EL) emission from GaAs-AlAs superlattices embedded in a p(+)-i-n(+) diode structure under forward bias. The occupation of higher subbands by sequential resonant tunneling between adjacent wells is demonstrated via interband emission. We observed emission lines due to transitions involving the second and third conduction subband as well as the third heavy-hole subband. The EL lines originating from higher subbands exhibit nearly a constant Stark shift indicating inhomogeneous electric field and carrier density distributions.