A GaAs surface was passivated simultaneously with S and Se using an optimized (NH4)2(S,Se)1.08 solution. X-ray photoelectron spectroscopy was used to analyze the surface composition and bonding states after several treatments of GaAs. It was revealed that the passivated surface mainly contained As-(S,Se) bonds. The passivating effect between S and Se could be compared by exposure of the passivated surface to air. During the exposure, the degradation of Se-bond was found to be faster than that of S-bond. However, during in situ annealing under ultra high vacuum conditions, a decrease of S/Se ratio with the temperature was observed. It was revealed that during the anneal, the bond exchange from As-(S,Se) to Ga-(S,Se) occured. Also, high vaporization pressure of S induced the decrease of S content. Because of this evaporation and bonds exchanging reaction, the apparent thermal stability of Se(Ga,As) was found to be higher than that of S-(Ga,As).
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry