Peer-Reviewed Journal Details
Mandatory Fields
Simcock, M. N.,He, L.,Pemble, M. E.
2002
June
Journal De Physique Iv
Reflectance anisotropy studies of the oxidation of (001) GaAs surfaces in an MOCVD reactor
Validated
()
Optional Fields
12
Pr4Pr4
25
2825
We have employed reflectance anisotropy spectroscopy (RAS) and dynamic reflectance anisotropy (RA) operating at 2.6 eV to monitor the influence of air on a freshly cleaned (001) GaAs surface prepared via heating under H-2 and AsH3 in an MOCVD reactor. RA transients have been obtained which correspond to the removal of surface dimers as a result of surface oxidation. It is demonstrated that the rate of change of the RA response is strongly dependent upon the rate of introduction of the air and show that the reaction proceeds, at least initially, by a pseudo-first order process. Experiments performed over a range of temperatures for fixed rate of gas introduction allow us to estimate the activation energy for the oxidation process. The value obtained, ca. 21 kJmol(-1), is representative of a facile process, which we speculate to arise from the reaction of surface Ga-As bonds exposed on the surface under the c(4x4)/d(4x4) surface reconstruction that is believed to form under the conditions employed.We have employed reflectance anisotropy spectroscopy (RAS) and dynamic reflectance anisotropy (RA) operating at 2.6 eV to monitor the influence of air on a freshly cleaned (001) GaAs surface prepared via heating under H-2 and AsH3 in an MOCVD reactor. RA transients have been obtained which correspond to the removal of surface dimers as a result of surface oxidation. It is demonstrated that the rate of change of the RA response is strongly dependent upon the rate of introduction of the air and show that the reaction proceeds, at least initially, by a pseudo-first order process. Experiments performed over a range of temperatures for fixed rate of gas introduction allow us to estimate the activation energy for the oxidation process. The value obtained, ca. 21 kJmol(-1), is representative of a facile process, which we speculate to arise from the reaction of surface Ga-As bonds exposed on the surface under the c(4x4)/d(4x4) surface reconstruction that is believed to form under the conditions employed.
1155-43391155-4339
://WOS:000176979500005://WOS:000176979500005
Grant Details