Controlled conductivity in iodine-doped ZnSe films grown by metalorganic vapor-phase epitaxy

Iodine-doped ZnSe films have been grown on GaAs by low-pressure metalorganic vapor-phase epitaxy using dimethylzinc and hydrogen selenide as reactants. In order to accomplish an accurate control of the carrier concentration in the films over a wide range, ethyliodide diluted to 1000 ppm was used as a dopant source. It has been shown that the carrier concentration can be changed in the range from 1015 to 1019 cm−3 by varying the flow rate of ethyliodide. Furthermore, the films with carrier concentrations below 1018 cm−3 exhibit strong blue emission with suppressed deep level emissions. The origin of blue emission has been ascribed to the iodine donors incorporated during growth. According to the results shown, it has been concluded that iodine is a superior donor dopant for ZnSe from a standpoint of the controllability and reproducibility of electrical and photoluminescence properties of the n-type films over a wide range.