Chemisorption-Induced Defects on GaAs(110) Surfaces

Chemisorption of Ge on GaAs(110) at 320 °C simultaneously introduces acceptor- and donor-type surface states with the same density. The acceptor levels were found to be linked to $E_{\mathrm{cs}}$. Under the assumption of the same behavior for the donor levels, the band bending versus coverage curve was calculated for samples at 20 °C, and very good agreement was found with the experimental data of Spicer et al. for metal overlayers on GaAs(110). It is concluded that chemisorption on GaAs(110) surfaces introduces a single type of defect.