GROWTH AND PROPERTIES OF IODINE-DOPED ZNS FILMS GROWN BY LOW-PRESSURE MOCVD USING ETHYLIODIDE AS A DOPANT SOURCE

Iodine-doped ZnS films have been grown by low-pressure metalorganic chemical vapor deposition using ethyliodide as a dopant source, and their electrical and optical properties have been investigated for several doping conditions. It is shown that the electron density can be controlled from 5 x 10(16) to 2 x 10(19) cm-3 by changing doping conditions. In photoluminescence properties at 18 K of iodine-doped samples, an excitonic emission bound to neutral shallow donors (I2) and a self-activated (SA) emission have been observed. It has been found that their intensities increase with electron density in lightly doped films. However, in heavily doped films the intensity of the I2 emission decreases with electron density and that of SA emission tends to saturate. Furthermore, it has been found that the incorporation rate of iodine into the films is affected by growth temperature and [VI]/[II] source gas molar ratio.