Controlled Polytypism in a Variable Bandgap Semiconductor.

摘要

The program investigated the feasibility of controlling the properties of Pb12 by selectively doping it with particular impurities. Researchers grew very high purity crystals of Pb12 consisting of only one polytype. They then regrew crystals from the purified material using selective dopants. Finally, a detailed characterization was performed of the material to determine the crystal structure and physical properties of the doped Pb12 samples. Measurements showed that the addition of dopant atoms to Pb12 altered the crystal structure of the Pb12 slightly, inducing the formation of 4H polytypes, but did not change the value of the semiconducting bandgap. Despite these anomalies, researchers were able to produce highly purified crystals of Pb12 which could potentially be very useful in a number of applications, particularly low noise optical detectors.