Time Resolution And Power Dependence Of Transistor Based Terahertz Detectors

We present a systematic study of time resolution and power dependence of the responsivity of three significantly different types of the Field Effect Transistor based detectors. We analyze photoresponse of custom-made Si junctionless FETs (JLFETs), Si MOSFETs and GaAs-based high electron mobility transistors (HEMT) detectors, which represent structures that are very often employed in experiments dedicated to the detection of sub-TItz and THz radiation using FETs. All structures have been monolithically integrated with a log-periodic broad-band planar antenna. Time resolved photoresponse of room temperature detectors have been studied applying nanosecond pulses of monochromatic linearly polarized terahertz laser radiation with frequencies ranging from 0.6 to 3.3 THz. Our measurements demonstrate that these detectors have nanoseconds response time and very wide dynamic range, both strongly depending on applied FET gate voltages..