GaAs(110) Surface Modifications Introduced by Hydrogen

Abstract

For the nanoscopic analysis of III/V nanowire surfaces, hydrogen cleaning is a commonly used procedure. While this is reported to achieve clean, atomically flat surfaces, the process and dynamics during the cleaning procedure are rarely examined. Here, we investigate the modifications of GaAs(110) as model system introduced by hydrogen supply at room temperature and under commonly used cleaning conditions at the atomic level by scanning tunneling microscopy and -spectroscopy. Understanding this dynamics is crucial for the interpretation of measurements concerning electronic surface properties as well as conductivity measurements, since the surface-to-volume ratio of nanowires is quite high. Clean, cleaved surfaces of n- and p-doped GaAs differ in their appearance as well as in their electronic behavior. These severe changes are analyzed and interpreted with the help of tunneling current simulations.