A comparative study of simulated and experimentally obtained nonuniformity in thermal and electrical properties of conducting films

Abstract

The effect of localized microwave absorption in conducting thin films had been simulated using a heat diffusion model to quantitatively evaluate the electrical voltage maps obtained recently using a near-field scanning microwave microprobe (NSMM) in combination with the I-V characterization. In the experiment, the focused microwave emitted from the NSMM at a sample spot of dimension comparable to the NSMM tip dimension changes the local resistivity of the sample via microwave heating. By measuring the voltage response while scanning the NSMM, nonuniformity in the electrical current distribution in the sample can be resolved. To quantitatively assess the effect of various parameters, a theoretical simulation of the temperature profile has been made and related to the voltage response profile obtained experimentally. The variation of the induced voltage due to microwave absorption with time, microwave input power, and the thickness of the film has also been studied and the simulation compares well with experiment. Discussions on discrepancies between simulation and experiment will also be presented.

Radio-Frequency Conductivity Characteristics and Corresponding Mechanism of Graphene/Copper Multilayer Structures

“…The results calculated by Turja Nandy further illustrate that the carrier concentration of Gr exhibits a positive temperature dependence [ 34 ]. Based on these results, it can be hypothesized that the transient thermogenesis (~404 K) induced when the high-frequency signal emitted by the tip of the needle interacts with the Gr during the SMIM test process [ 33 , 35 ] results in an elevation of Gr Fermi energy level, leading to the increasing of carrier concentration, as shown in Figure 4 b. Considering the significantly higher carrier mobility of Gr and the notably increased carrier concentration of Gr at high frequencies, it can be concluded that based on the classic Drude model.…”

Combining Near-Field Scanning Microwave Microscopy With Transport Measurement for Imaging Current-Obstructing Defects in HTS Films

“…Preliminary work on the application of this technique on conducting silver thin films has been done previously [5] and supporting numerical simulations have also been carried out to gain a better understanding of the mechanism of heat absorption in films by microwave irradiation [6]. In this paper, we present results on applying this technique for imaging current-obstructing defects in YBCO thin films.…”