Heat flow in InAs/InP heterostructure nanowires

Abstract

The transfer of heat between electrons and phonons plays a key role for thermal management in future nanowirebased devices, but only a few experimental measurements of electron-phonon (e-ph) coupling in nanowires are available. Here, we combine experimental temperature measurements on an InAs/InP heterostructure nanowire system with finite element modeling to extract information on heat flow mediated by e-ph coupling. We find that the electron and phonon temperatures in our system are highly coupled even at temperatures as low as 2 K. Additionally, we find evidence that the usual power-law temperature dependence of electron-phonon coupling may not correctly describe the coupling in nanowires and show that this result is consistent with previous research on similar one-dimensional electron systems. We also compare the strength of the observed e-ph coupling to a theoretical analysis of e-ph interaction in InAs nanowires, which predicts a significantly weaker coupling strength than observed experimentally.

Quantum Confinement Suppressing Electronic Heat Flow below the Wiedemann–Franz Law

“…Interestingly, this leads to an e-ph coupling constant comparable to that of a metal, in spite of the electron density being several orders of magnitude smaller. This finding is consistent with the strong e-ph coupling found in InAs above 1 K 32 possibly due to piezoelectricity 42 and/or a lateral-confinement-enhanced peaked density of states. 43 We observe the e-ph contribution to change linearly with V g (see associated plot and analysis in the Supporting Information ) implying that the e-ph coupling constant is proportional to the charge carrier density.…”

“… 31 Although entering directly in the thermoelectric efficiencies, the electronic heat conductance of such devices is in general not measured independently. Because at temperatures above a few degrees Kelvin, the thermal transport properties of InAs nanowires are known to be strongly dominated by phonons, 32 the electronic heat conductance of InAs can only be experimentally probed at milliKelvin temperatures.…”

Nonlinear thermovoltage and thermocurrent in quantum dots

“…Owing to thicker InP barriers than those of QD1, the FWHM of the transmission function of QD2 can only be quantified as much less than kT (T = 590 mK). Finally, QD3 consisted of a 72 nm diameter InSb nanowire grown by [18,36]. (b) Differential conductance measured at T 0 = 240 mK as a function of gate voltage (converted to energy using the gate lever arm).…”

Hot-carrier optoelectronic devices based on semiconductor nanowires

“…131 This interpretation required the assumption of a coupling strength between electrons and acoustic phonons three orders of magnitude stronger than previously predicted by theory. 131 Quantum wires formed at an InGaAs/InAlAs interface showed the energy loss rate per electron in the wire more than doubling compared to bulk, at electron temperatures of a few K. This could be indicative of an increased electron-phonon coupling strength, here ascribed to the singularities in the quasi-1D density of states. 132 Conversely, more direct probing of the electron-phonon coupling strength by resonant Raman spectroscopy shows the electron-LO-phonon coupling strength decreasing with diameter in ZnO 133 and ZnTe 134 nanowires (Fig.…”