Large-area sub-micron gap interdigitated THz emitters fabricated by interference lithography and angle evaporation

Interference-lithography and a self-aligning angle-evaporation technique are employed to fabricate interdigitated photoconductive terahertz (THz) emitters. The devices have a large active area for high directivity and submicron spaced electrodes for high internal electric fields at low bias voltages. The fabrication process offers the advantage that only one patterning step is needed to generate three isolated metallic structures. This avoids critical alignment and reduces the fabrication effort significantly. Voltage dependent THz emission is observed from 4 V upwards.