Theoretical Investigation Of Structural Stabilities And Electronic Properties Of Te Nanostructures

Tellurium plays an important role in the semiconductor industry for its excellentelectronic properties. Tellurium nanostructures, such as Te nanowires and Te nanobelts, areknown to be a promising candidate for various optoelectronics devices application. Based onthe experimental and theoretical researches, structural stability and electronic properties of Tenanowires and nanobelts are determined by the shape, size and surface morphology.Tellurium is known to be a promising candidate for various optoelectronics devicesapplication. In this work, we report on the geometry asymmetry induced charge separation inone dimensional Te nanostructures. We have performed a systematic investigationtheoretically on the structural stabilities and electronic properties of Te nanowires andnanobelts. Combining the bond energy model and the first-principles calculations, werevealed that the nanowires with hexagonal cross-sections are the most stable with smallestsurface-to-volume ratio, while the nanobelts synthesized experimentally are meta-stable dueto the growth kinetics. Our model analysis showed that the difference of next neighbors’distribution would induce a net dipole and simultaneously produce an intrinsic electric fieldinside the Te nanobelts. The internal electric field makes the charge distribution of valencebands and conducting bands separated at the two ends of Te nanobelts, and further induces thesemiconductor-metal transitions which have been verified by the first-principles calculations.Our finding provides a new insight into the mechanism of charge separation andsemiconductor-metal transitions, attributed to the geometry asymmetry.We also investigated the adsorption of H, F and H2O on Te nanobelts using thefirst-principles calculations. The calculated results show that H, F would induce p-typeconduction, while the electronic properties with the adsorbed H2O remain unchanged due tomuch weaker bonds between H2O and Te nanobelts. The result showed that the electronicproperties of Te nanobelts can be modulated by the adsorbed atoms and molecules.