The Fermi level position in as‐grown GaInNAs(Sb) quantum wells and layers studied by contactless electroreflectance

Abstract

AbstractIt is shown that the Fermi level in as‐grown GaInNAs(Sb) material wants to be pinned at an energy which is located very close to the Fermi level‐stabilization energy (EFS). For 7.5‐nm‐thick GaInNAs(Sb) layers (quantum wells in fact) this energy lies ∼0.9 eV above the GaAs valence band whereas the EFS is known to be located ∼4.9±0.2 eV below the vacuum level (∼0.6 eV above the GaAs valence band). Increased the GaInNAs(Sb) layer thickness to 100 nm the Fermi level pinning shifts closer to the Fermi level‐stabilization energy and is located ∼0.8 eV above the GaAs valence band. This observation is associated with this fact that the ability to pin the Fermi level close to the EFS enhances when the total number of N‐related native point defects increased. In this case, the total number of point defects increases because of the increase in GaInNAs(Sb) thickness. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)