We propose an antenna-less unbiased CW terahertz photomixer comprising an array of recessed contact electrodes. Each unit of the recessed contact electrodes array embedded in the photoconductive layer in-cludes two pairs of unsymmetrical metals making up heterogeneous Schottky contacts. As compared to the analogous array emitters of the same size with planar electrodes, by optimizing the geometrical and physical properties of the recessed contact electrodes in the proposed emitter to excite the appropriate resonant modes in the larger volume of the active region, it is possible to benefit from the having of high optical absorption and so terahertz photo-current, which in turn leads to enhance the obtainable THz power by more than three orders of magnitude. This is also more than an order of magnitude larger THz power than that is radiated from the similar antenna-coupled emitter with planar contact electrodes. Furthermore, the calculation results show the proposed emitter has a frequency tuning capability in a broad range of 0.1–5 THz.
