In a GaN/AlGaN field-effect terahertz detector, the directional photocurrent is mapped in the two-dimensional space of the gate voltage and the drain/source bias. It is found that not only the magnitude, but also the polarity, of the photocurrent can be tuned. A quasistatic self-mixing model taking into account the localized terahertz field provides a quantitative description of the detector characteristics. Strongly localized self-mixing is confirmed. It is therefore important to engineer the spatial distribution of the terahertz field and its coupling to the field-effect channel on the sub-micron scale.
@article{arxiv.1203.1386,
title = {Probing and modelling the localized self-mixing in a GaN/AlGaN field-effect terahertz detector},
author = {J. D. Sun and H. Qin and R. A. Lewis and Y. F. Sun and X. Y. Zhang and Y. Cai and D. M. Wu and B. S. Zhang},
journal= {arXiv preprint arXiv:1203.1386},
year = {2015}
}