Thermoelectromechanical effects in quantum dots

Abstract

Electromechanical effects are important in semiconductor nanostructures as most of thesemiconductors are piezoelectric in nature. These nanostructures find applications inelectronic and optoelectronic devices where they may face challenges for thermalmanagement. Low dimensional semiconductor nanostructures, such as quantum dots (QD)and nanowires, are the nanostructures where such challenges must be particularly carefullyaddressed. In this contribution we report a study on thermoelectromechanical effects inQDs. For the first time a coupled model of thermoelectroelasticity has been applied to theanalysis of quantum dots and the influence of thermoelectromechanical effects onbandstructures of low dimensional nanostructures has been quantified. Finiteelement solutions are obtained for different thermal loadings and their effectson the electromechanical properties and bandstructure of QDs are presented.Our model accounts for a practically important range of internal and externalthermoelectromechanical loadings. Results are obtained for typical QD systemsbased on GaN/AlN and CdSe/CdS (as representatives of III–V and II–VI groupsemiconductors, respectively), with cylindrical and truncated conical geometries. Thewetting layer effect on electromechanical quantities is also accounted for. Theenergy bandstructure calculations for various thermal loadings are performed.Electromechanical fields are observed to be more sensitive to thermal loadings in GaN/AlNQDs as compared to CdSe/CdS QDs. The results are discussed in the context ofthe effect of thermal loadings on the performance of QD-based nanosystems.