The interaction of 150 keV protons with a high-doped n-GaAs crystal has bee
n investigated by X-ray diffraction at grazing incidence (XRDGI), photorefl
ectance (PR), photoluminescence (PL) and scanning electron microscopy (SEM)
. The measurements confirmed that simultaneous with almost full loss of the
semiconducting properties of the surface crystal region after applying the
10(15) proton/cm(2) dose, (111) oriented extended type of crystalline defe
ct was formed. These defects have been identified as the (111) planes rotat
ed by similar to 40 degrees with respect to the (111) planes of the undistu
rbed GaAs cubic structure. They are located at the hydrogenated GaAs layer/
GaAs interface and induced by two effects: formation of microcracks prolong
ed throughout the implanted layer in 111 direction up to undisturbed GaAs c
rystal and strain arising at the corresponding interface. The role of the s
urface microcracks formed in the uppermost part of the reference sample as
a consequence of unsuitable mechano-chemical polishing procedures in the ev
olution of the effect observed is also discussed. (C) 1999 Elsevier Science
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