Large enhancement of the thermoelectric figure of merit in a ridged quantum well - Condensed Matter > Mesoscale and Nanoscale PhysicsReport as inadecuate




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Abstract: Recently new quantum features were observed and studied in the ridged quantumwells RQW. Periodic ridges on the surface of the quantum well layer imposeadditional boundary conditions on electron wave function and reduce quantumstate density. As result, chemical potential of RQW increases and becomes theridge height dependent. Here we propose system comprising of RQW and additionallayer on the top of the ridges forming periodic series of p+-n+ junctions ormetal-n+ junctions. In such systems charge depletion region develops insidethe ridges and effective ridge height reduces, becoming rather strong functionof temperature T. Consequently, T dependence of chemical potential magnifiesand Seebeck coefficient S increases. We investigate S in the system ofsemiconductor RQW having abrupt p+-n+ junctions or metal-n+ junctions on thetop of the ridges. Analysis made on the basis of Boltzmann transport equationsshows dramatic increase in S for both cases. At the same time other transportcoefficients remain unaffected by the junctions. Calculations show one order ofmagnitude increase in thermoelectric figure of merit ZT relative to the bulkmaterial.



Author: Avto Tavkhelidze

Source: https://arxiv.org/







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