Temperature characteristics of resonant-tunneling devices

Abstract

For Si1-xGex/Si hole and Ga1-xAlxAs/GaAs electron double barrier resonant tunneling devices (RTDs), we have studied the negative differential resistance (NDR). The current peak-to-valley ratio (PVR) was investigated as function of the temperature T for different device parameters and the dependence of the maximum working temperature Tm on material parameters and device parameters was determined. The results show that by narrowing well and barrier width, decreasing barrier height, and decreasing the doping concentration in the spacer layer, the RTDs have improved temperature characteristics, and have higher peak current Jp and larger PVR at high temperature. The RTDs with larger well width, and wide and high barriers nave quite large PVR, and are favorable to use at low temperature. Ga1-xAlxAs/GaAs electron RTDs are estimated to work at room temperature for a wide range of device parameters, while the device parameter design of Si1-xGex/Si hole RTDs is much more critical to work at same temperature. These results are consistent with the tendency of recently published experiments. On the basis of calculated PVR curves we can optimize RTD parameters to increase the working temperature and current peak-to-valley ratio.