Disordering of natural superlattice in (Ga,In)P induced by electron irradiation

Abstract

We have found that disordering of the Cu-Pt type ordered structure in (Ga,In)P occurs in a transmission electron microscope under intense electron irradiation with electron fluxes of \ensuremath{\varphi}=1.6, 4.7, and 7.8\ifmmode\times\else\texttimes\fi{}${10}^{18}$ electrons ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. The electron diffraction intensity of the ordered spots decreased exponentially with increasing irradiation time. The threshold incident-electron energy for the disordering is estimated to be about 150 keV, which is related to that for atomic displacement at the Ga and In sites. The rate of disordering depends on temperature. Applying the rate theory of point defects, a correlated recombination factor under electron irradiation (the probability that the displaced Ga or In atom returns to the primary site) is estimated to be 0.75 in the temperature range 83 to 300 K and 0.4 at 20 K. \textcopyright{} 1996 The American Physical Society.