Electrical Instability of CdTe:Si Crystals

<span>Results of Hall effect measurements of cadmium telluride crystals, doped by silicon (dopant concentration in the melt was 10</span>¹⁸<span> - 10</span>¹⁹<span> cm</span>^-3<span>), allowed to classify the studied samples and the conditions under which probably the definite crystal and impurity states are realized. We have found the distinction between 3 type of CdTe:Si crystals: (1) low-resistance p-type crystals with shallow acceptors, in which Si impurity is localized mainly in the large inclusions; (2) semi-insulating crystal with deep acceptors and submicron size dopant precipitates that are source/drain for interstitials Si</span>_i<span> - shallow donors; and (3) low-resistance crystals in which the n-type conductivity is provided by shallow donors: Si</span>_i<span> (and/or SiCd). Therefore the silicon is responsible for n-type conductivity of doped samples, introducing as a donor Siі and provides semi-insulating state by forming deep acceptor complexes (Si</span>_Cd-<span>V</span>_Cd2-<span>)- with (Еv + 0.65 eV). Besides, the submicron silica precipitates, that have a tend to "dissolution" at relatively low temperatures, can act as electrically active centers. </span><strong><br />Keywords: </strong><span>cadmium telluride, silicon, doping, electrical properties, impurity, precipitates.</span>