Influence of electrode parameters on the performance of optically controlled MESFETs

The effects of electrode spacing on the optical response of illuminated MESFETs are analyzed. The analysis targets various optical performance factors including terminal photocurrent peak value, peak-time and discharge time. Whereas photocurrent peak value increases nonlinearly with electrode spacing, it was found that increasing the electrode spacing has a profound effect on the ability of the device to flush-out the optically generated carriers and hence more output delays are generated. A figure-of-merit has been defined to quantify the overall spacing effects. The simulation results show that optimum electrode spacing can be achieved.