Browsing by Author "Chen, Kejian"

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Comparison of continuous-wave terahertz wave generation and bias-field-dependent saturation in GaAs:O and LT-GaAs antennas
(2009-04-01)
Chen, Kejian
;
Li, Yu-tai
;
Yang, Mong-huan
;
Cheung, Wing Yiu
;
Pan, Ci-Ling
Terabertz wave (THz) photoconductive (PC) antennas were fabricated on oxygen-implanted GaAs (GaAs:O) and low-temperature-grown GaAs (LT-GaAs). The measured cw THz power at 0.358 THz from the GaAs:O antenna is about twice that from the LT-GaAs antenna under the same testing conditions, with the former showing no saturation up to a bias of 40 kV/cm, while the latter is already beginning to saturate at 20 kV/cm. A modified theoretical model incorporating bias-field-dependent electron saturation velocity is employed to explain the results. It shows that GaAs:O exhibits a higher electron saturation velocity, which may be further exploited to generate even larger THz powers by reducing the ion dosage and optimizing the annealing process in GaAs:O. (C) 2009 Optical Society of America
CW sub-terahertz wave generation by GaAs : O materials
(2007-01-01)
Chen, Kejian
;
Li, Yutai
;
Cheung, WingYiu
;
Wang, Weiwen
;
Pan, CiLing
Oxygen Implanted GaAs was used for terahertz wave emitter fabricatiom CW Terahertz waves are measured from this kind of material. We take sampling in the range of 0.25 to 0.5 THz. The measured output power is in ten nW range.