No abstract

This study investigates the effect of temperature on the emission frequency of an intrinsic Josephson junction terahertz (THz) electromagnetic wave source, which can be used for high-speed communications by THz carrier wave. The characteristic emission features of two device types (asymmetric and symmetric) and two bias regimes (low and high) were determined. The biasdependent emission frequency was temperature dependent in the asymmetric device, most likely reflecting the temperature-dependent London penetration depth. The bias tunability of the emission frequency can be explained by device self-heating, which significantly and inhomogeneously raises the temperatures of the device from its bath temperature. These findings are consistent with previous studies of temperature distribution in these devices. V C 2015 AIP Publishing LLC. FIG. 4. (a) Plots of emission frequency f e vs averaged resistance R c (filled symbols; top axis) and bias voltage V (open symbols; bottom axis) of Device C. The same colors represent data at the same temperature. The solid line is the ac Josephson relation. (b) Toy model of a mesa with an inhomogeneous temperature distribution. A gray solid curve represents the excited electromagnetic wave inside the stack. 043914-4Kakeya et al.