Effect of iodine-doping in the deposition solution and iodine vapor pressure during the sensitization process on the morphological, microstructural, electrical, and optical properties of PbSe films was studied. Undoped and iodine-doped PbSe films of polycrystalline particles were coated on thermally oxidized silicon substrates by chemical bath deposition. The PbSe films were oxidized at 380°C for 30 min and then iodinated at different iodine vapor pressures at 380°C for 5 min. When the iodine vapor pressure was below 20 Pa, PbSeO3 was the main phase formed on the surface of PbSe microcrystals for both undoped and iodine-doped films. As the iodine vapor pressure was increased above 20 Pa, Pb3I2O2 and PbI2 phases were formed in both types of films and PbSeO3 disappeared in the undoped film. Only the iodine-doped films showed photo response. The sheet resistance and IR signal-to-noise ratio had maximum values at the iodine vapor pressure of 17.5 Pa in the iodine-doped film. The x-ray diffraction spectra, scanning electron microscopy morphologies, and EDS analyses of the sensitized PbSe films show that the main role of iodine in the sensitization is helping solid-state sintering of PbSe microcrystals which may lead to redistribution of oxygen atoms in the effective atomic sites.
Influence of iodine vapor pressure during the sensitization process on the morphology, microstructure, and electrical properties of the PbSe films was studied. PbSe films of polycrystalline particles were coated on thermally oxidized silicon substrates by chemical bath deposition using a solution of lead acetate and sodium selenosulfate without or with iodine-doping. As-grown PbSe films were oxidized at 380°C for 30 min and then treated with iodine vapor of different pressures at 380 °C for 5 min. As the iodine vapor pressure was increased above 20 Pa during the iodination process, the PbI2 phase begins to form in the undoped films, while the PbI2O2 and Pb3O4 phases as well as PbI2 are formed in the iodine-doped films. Only iodine-doped films showed photo response. The sheet resistance and the signal to noise ratio increased with the iodine vapor pressure up to the 17.5 Pa iodine pressure. The role of iodine in the sensitization is thought to be helping recrystallization of PbSe grains and the resultant redistribution of oxygen atoms in the effective atomic sites.
The temperature gradient at the growth interface is as important as the growth temperature and the growth rate for growing CdTe single crystals by the Traveling Heater Method (THM). This article presents the results of an experimental study of the influence of the growth temperature gradient on THM growth of CdTe single crystals. CdTe crystals were grown at about 900°C with the growth rate of 10 mm/day and the rotation rate of 3 rpm. With the growth temperature gradient of about 30 °C/cm even a single-grain structure became a multi-grain structure in the final stage of growth. On the other hand, with the growth temperature gradient of about 50 °C/cm, even if the crystal started with multi-grains, it became a single crystal eventually. The constitutional supercooling criterion was used to interpret these results.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.