Journal of Vacuum Science & Technology A Vacuum Surfaces and Films · 1995 · 18 citations · 0 references
EngineeringMaterials SciencePhysicsInterface ScienceSemiconductor DevicesSemiconductor MaterialsQuantum TunnelingSemiconductor Device MaterialsSemiconductor HeterostructuresSemiconductor InterfacesSemiconductor PhysicsSemiconductor SurfacesInterface CharacterizationResonant TunnelingResonant Tunneling DevicesScanning Tunneling SpectroscopySemiconductor CharacterizationTunneling DiodesValence Band StructureValence-band Spectroscopy
A lattice-matched InP/InGaAs resonant tunneling diode is studied by scanning tunneling microscopy and spectroscopy. Results show both a structural and chemical asymmetry between the normal and inverted interfaces. The inverted (InP on InGaAs) interface is considerably rougher than the normal interface, and the frequency components of the roughness at both interfaces have been calculated. Additionally, certain images show enhanced and reduced state densities at the normal and inverted interfaces, respectively, which is most likely due to dissimilar bonding types at the interfaces. Spectroscopic observations of evanescent valence-band states tailing into the InP barrier allow for direct measurement of the valence-band offset.