Thermal-aware device design of low-power H2S sensors using Joule-heated Au nanosheet

Abstract

We demonstrated Joule-heated Au nanosheet H2S sensors for low-power operation. We confirmed that low temperature regions in the Joule-heated Au nanosheet caused lower response and recovery characteristics than uniformly heated Au nanosheets. By using Pt electrodes, which has lower thermal conductivity than Au, heat dissipation to the electrodes could be suppressed, resulting in lower power consumption and faster recovery characteristics. We then discussed the optimal sensor structure by developing an analytical model of electrical and thermal resistances. We introduced semi-elliptical intermediate electrodes between the channel and pad electrodes to efficiently suppress the heat dissipation, demonstrating that the optimal channel length and thermal conductivity of the intermediate electrode κ int exist depending on the channel width. Finally, we proposed the sensor design strategy of considering the κ int dependences of the electrical and thermal resistances. This strategy is useful for all metal nanosheet sensors because it gives an estimation of their optimal structures.