Abstract-Carbon irradiated semi insulating GaAs for photoconductive terahertz pulse detection

Carbon irradiated semi insulating GaAs for photoconductive terahertz pulse detection Abhishek Singh, Sanjoy Pal, Harshad Surdi, S. S. Prabhu, S. Mathimalar, Vandana Nanal, R. G. Pillay, and G.H. Döhler  »View Author Affiliations

Optics Express, Vol. 23, Issue 5, pp. 6656-6661 (2015)
http://dx.doi.org/10.1364/OE.23.006656

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We report here a photoconductive material for THz detection with sub-picosecond carrier lifetime made by C¹² (Carbon) irradiation on commercially available semi-insulating (SI) GaAs. We are able to reduce the carrier lifetime of SI-GaAs down to sub-picosecond by irradiating it with various irradiation dosages of Carbon (C¹²) ions. With an increase of the irradiation dose from ~10¹² /cm² to ~10¹⁵ /cm² the carrier lifetime of SI-GaAs monotonously decreases to 0.55 picosecond, whereas that of usual non-irradiated SI-GaAs is ~70 picosecond. This decreased carrier lifetime has resulted in a strong improvement in THz pulse detection compared with normal SI-GaAs. Improvement in signal to noise ratio as well as in detection bandwidth is observed. Carbon irradiated SI-GaAs appears to be an economical alternative to low temperature grown GaAs for fabrication of THz devices.

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