Acceptors in Donor-Doped GaAs Resulting from Li Diffusion

Abstract
Experiments have been carried out on Te‐doped (∼1–3×1018 cm−3) GaAs crystals in which changes in n are measured when Li is introduced by diffusion and again after the Li is removed. The amounts of Li removed are determined by chemical analyses. It is found that two Li atoms introduced cause a loss of one electron, corresponding to a (Li+Li=) pair. Acceptors remain during the removal of Li which are postulated to be Ga vacancies. The kinetics of the disappearance of the ``vacancies'' have been investigated. The process appears to be diffusion controlled with an activation energy corresponding to 5–6 eV. The equilibria reached show an increasing ``vacancy'' solubility with decreasing temperature. A model in which Ga vacancies form stable pairs with Te atoms is discussed.

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