Ehret, S.S.EhretSchneider, H.H.SchneiderLarkins, E.C.E.C.LarkinsRalston, J.D.J.D.Ralston2022-03-032022-03-031995https://publica.fraunhofer.de/handle/publica/18722010.1063/1.3587832-s2.0-0043213590We report on experimental and theoretical investigations of the dark current behavior in n-type GaAs/AlAs/Al sub0.3 Ga sub0.7 As double-barrier quantum wells (DBQW). The dark current perpendicular to the 50-period DBQW structures shows evidence of tunneling through the 2-nm-wide AlAs tunnel barriers and thermionic emission across the 25-nm-wide AlGaAs layers. The temperature dependence is in good agreement with our numerical simulations, using an effective escape rate of 2.2 x 10 high14 s high-1. The dark current is further modified by internal electric fields caused by an asymmetric dopant distribution, which partially arises from a dopant segregation during epitaxial growth. We also present a theoretical simulation showing how the dark current versus voltage dependence is influenced by these space-charge fields.enphotovoltaicthermionic emissionthermische Emissiontunneling621667530journal article