Abstract
Recent positron lifetime studies made on the Au/GaAs interface with an applied electric field returning a significant fraction of bulk implanted positrons to the interface have revealed the presence of microvoids(≈ 1 nm diameter) at the interface. In this work an attempt has been made to study these microvoids by observing the Doppler broadening on the annihilation radiation coming from them. This is done both by observing theS-parameter as a function of applied bias and by applying the generalized least-squares method to the deconvolution of the annihilation radiation lineshape. The general conclusion is that the Doppler-broadened data are consistent with the majority of positrons trapping into microvoids, probably associated with grain boundaries. The data suggest that these open volume defects are more associated with the Au film rather than the Au-Ga alloyed interfacial region.
Similar content being viewed by others
References
G. Dlubek, R. Krause: Phys. Status Solidi (a)102, 443 (1987)
P.J. Schultz, K.G. Lynn: Rev. Mod. Phys.60, 701 (1988)
S. Dannefaer, P. Mascher, D. Kerr: J. Phys. C1, 3213 (1989)
K. Saarinen, P. Hautojärvi, P. Lanki, C. Corbel: Phys. Rev. B44, 10585 (1991)
Y.Y. Shan, H.L. Au, C.C. Ling, T.C. Lee, B.K. Panda, S. Fung, C.D. Beling, Y.Y. Wang, H.M. Weng: Appl. Phys. A58, 1 (1994)
C.D. Beling, R.I. Simpson, M.G. Stewart, Y.Y. Wang, S. Fung, J.C.H. Wai, T.N. Sun: Phys. Status Solidi (a)102, 537 (1987)
W. Shockley: Bell Syst. J.30, 990 (1951)
C.C. Ling, T.C. Lee, S. Fung, C.D. Beling, H.M. Weng, J.H. Xu, S.J. Sun, R.D. Han: J. Phys. C,6, 1133 (1994)
B.K. Panda, S. Fleisher, C.C. Ling, C.D. Beling, S. Fung, S. Panda: Appl. Surf. Sci.85, 182 (1995)
G.B. Bachelet, D.R. Hammann, M. Schlüter: Phys. Rev. B26, 4199 (1982)
D.M. Ceperley, B.J. Alder: Phys. Rev. Lett.45, 566 (1980) and as parameterized by J.P. Perdew, A. Zunger: Phys. Rev. B23, 5048 (1981)
M.J. Puska, O. Jepsen, O. Gunnarsson, R.M. Nieminen: Phys. Rev. B34, 2695 (1986)
K. Kumar: Jpn. J. Appl. Phys.18, 713 (1979)
X.F. Zeng, D.D.L. Chung: Thin Solid Films93, 207 (1982)
T. Yoshie, C.L. Bauer, A.G. Milnes: Thin Solid Films111, 149 (1984)