Unique band bending at the Sb/InP(110) interface

Abstract

The band bending and the overlayer growth at the Sb/InP(110) interface has been studied with soft x-ray photoemission spectroscopy. In agreement with previous works, our data indicate that 1 monolayer (ML) of Sb is growing in a laminar zig–zag fashion on the unrelaxed substrate. This is consistent with models previously applied to the Sb/GaAs interfaces. We, however, observe some puzzling behaviors unique to the Sb/InP(110) interface. First, we find that for this model system with simple morphology the core level shifts, routinely taken as a measure of the band bending, are different for In 4d and P 2p. This perhaps could indicate a presence of another component but also could indicate some problems in using photoemission in application to the quantitative band bending studies. Despite pronounced quantitative differences, we assumed that the core level movement is dominated by the band bending and find for both core levels a reversal of shift on n-InP indicating reversal of the band bending from a maximum at ∼0.5 ML to a small value of 0.15±0.1 eV (0.1 or 0.2 eV depending on the core level monitored) for few monolayers of Sb. These data are consistent with previous results using Raman spectroscopy and electrical diode measurements which find Ohmic contacts for thick Sb overlayers on InP(110). Also consistent with these works, we find large band bending on p-InP(110).