Observation of direct tunneling conduction for TDTFT in high temperatures

We calculated the tunneling current in the high temperatures and discussed the dominant conduction mechanism of TDTFT. Although the discrepancy between the measured and the calculated data is approximately one order, the increase ratio of I_d to absolute temperature is nearly equal for the measured and the calculated one. These data strongly indicate that the dominant mechanism of the I_d in the high temperatures for the TDTFT is direct tunneling (DT) from the tail area in the Fermi-Dirac distribution function of Al.