2D Materials for Universal Thermal Imaging of Micro- and Nanodevices: An Application to Gallium Oxide Electronics
James Spencer Lundh, Tianyi Zhang, Yuewei Zhang, Zhanbo Xia, Maxwell Wetherington, Yu Lei, Ethan Kahn, Siddharth Rajan, Mauricio Terrones, Sukwon Choi
Abstract
We highlight the flexibility of two-dimensional (2D) materials for advancing current technologies through the introduction of 2D Raman thermography (2DRT). 2DRT combines monolayer materials and Raman spectroscopy to perform thermal imaging of micro- and nanodevices. In contrast to peak shift and line width based methods for Raman thermal analysis, 2DRT uses the anti-Stokes/Stokes intensity ratio which is only sensitive to temperature. To demonstrate the technique, monolayer molybdenum disulfide (MoS2) was transferred to the surface of devices based on β-gallium oxide (Ga2O3), an emerging ultrawide-bandgap semiconductor for high-frequency and high-power applications. The validation of the technique was performed on an (AlGa)2O3/Ga2O3 modulation-doped field effect transistor by using nanoparticle-assisted Raman thermometry. The peak operating temperature, a critical device performance metric, is underestimated by ∼30% by using standard Raman thermometry when compared to 2DRT. Finally, the 2D thermal imaging capabilities of 2DRT were demonstrated on an (AlGa)2O3/Ga2O3 transmission line measurement structure.