This study describes the design of a resonant tunneling diode (RTD) oscillator (RTD oscillator) with a RTD-gated-graphene-2DEF (two dimensional electron fluid) and demonstrates the functioning of this RTD oscillator through a transmission line simulation model. Impedance of the RTD oscillator changes periodically when physical dimension of the device is of considerable fraction of the electrical wavelength. As long as impedance matching is achieved, the oscillation frequency is not limited by the size of the device. An RTD oscillator with a graphene film and negative differential resistance (NDR) will produce power amplification. The positive electrode of the DC power supply is modified and designed as an antenna. So, the reflected power can also be radiated to increase RTD oscillator output power. The output analysis shows that through the optimization of the antenna structure, it is possible to increase the RTD oscillator output to 22 mW at 1.9 THz and 20 mW at 6.1 THz respectively. Furthermore, the RTD oscillator has the potential to oscillate at 50 THz with a matching antenna.

This study proposes an on-chip terahertz (THz) detector designed with on-chip inset-feed rectangular patch antenna and catadioptric lens. The detector incorporates a dual antenna and dual NMOSFET structure. Radiation efficiency of the antenna reached 89.4% with 6.89 dB gain by optimizing the antenna inset-feed and micro-strip line sizes. Simulated impedance was 85.55 − j19.81 Ω, and the impedance of the antenna with the ZEONEX horn-like catadioptric lens was 117.03 − j20.28 Ω. Maximum analyzed gain of two on-chip antennas with catadioptric lens was 17.14 dB resonating at 267 GHz. Maximum experimental gain of two on-chip patch antennas was 4.5 dB at 260 GHz, increasing to 10.67 dB at 250 GHz with the catadioptric lens. The proposed on-chip rectangular inset-feed patch antenna has a simple structure, compatible with CMOS processing and easily implemented. The horn-like catadioptric lens was integrated into the front end of the detector chip and hence is easily molded and manufactured, and it effectively reduced terahertz power absorption by the chip substrate. This greatly improved the detector responsivity and provided very high gain. Corresponding detector voltage responsivity with and without the lens was 95.67 kV/W with NEP = 12.8 pW/Hz^0.5 at 250 GHz, and 19.2 kV/W with NEP = 67.2 pW/Hz^0.5 at 260 GHz, respectively.

The rapid thermal annealing process is a key technology to control the parameters of the resonant tunneling diode (RTD) and to achieve high performance for the device. In this paper, the rapid thermal annealing process on the planar RTD has been investigated experimentally. In the experiment, the annealing sample chips of different annealed times have been recorded from the annealing equipment and their I–V characteristics have been measured accordingly. From the I–V characteristics, the negative resistance and the series resistance of the RTD can be obtained. Thus, the relationship between these parameters and annealing time can be established. Finally, by analyzing the concept of the resistance compensation effect, this study explains fully and in detail the dependency of the RTD parameter variation on the annealing time. V_P and V_i are significantly reduced, greatly lowering R_S, which in return also reduces the heat loss of the circuit and the power consumption of the RTD digital circuits as well as the RTD terahertz oscillator. As V_V decreases, negative resistance R_N is increased, and thus, the output power of the RTD terahertz oscillator is increased. These results are very useful in the study of RTD devices and fabrication technology.