Chemical bonding and electronic properties of SeS2-treated GaAs(100)

Abstract

SeS 2 -passivated n-type GaAs ͑100͒ surfaces, formed by treatment of GaAs in SeS 2 :CS 2 solution at room temperature, were studied with high-resolution core-level photoemission spectroscopy excited with synchrotron radiation source. The SeS 2 -treated surface consists of a chemically stratified structure of several atomic layers thickness. Arsenic-based sulfides and selenides reside in the outermost surface layer while gallium-based selenides are adjacent to the bulk GaAs substrate. The shift of the surface Fermi level within the band gap was monitored during controlled thermal annealing, allowing for the identification of the specific chemical entities responsible for the reduction in surface band bending. Arsenic-based species are removed at low annealing temperature with little shift of the Fermi level. Gallium-based selenides are shown to be associated with the unpinning of the surface Fermi level.

Compositional Study of Copper-Germanium Ohmic Contact to n-GaN

“…The close vicinity of the low-binding energy Ga 3d core level peak to the valence band makes movement of this peak a good indication of shifts of the valence band edge, 13 and shifts of this peak have been averaged with shifts of E V in Fig. 3a to reduce extrapolation errors present in estimates of E V .…”

ZnO–GaN tunnel junction for transparent ohmic contacts to p-GaN

“…The displacement of the binding energy of Ga (3d) core level, being the measure of the Fermi level shift at the GaN surface [10], corresponds to the band bending at the interface caused by the given technological step. In the spectrum labelled a, representative of a clean p-GaN surface, the Ga (3d) peak is centred at 19.6 eV, which compares well with values 19 [11] and 20 eV [12] reported for similar p-GaN samples.…”

Effect of SeS2 treatment on the surface modification of GaAs and adhesive wafer bonding of GaAs with Silicon

“…The passivation was done for different timings of 5, 10 and 15 s at room temperature. All the passivated samples were directly annealed at 350 C in nitrogen for 10 min so as to enable them for adhesive wafer bonding with silicon by overcoming problems of surface band bending by Asto-Ga atomic concentration ratio, As-S and As-Se based weaker bonds [9,10]. The crystalline phase modifications of SeS 2 treated GaAs (1 0 0) were directly measured by powder XRD analysis from 30 to 100 at a rate of 1 /min using Rich Seifert diffractometer (Model No.…”