Photomixers fabricated on nitrogen-ion-implanted GaAs

• Published in: Applied physics letters 2005-07, Vol.87 (4), p.041106-041106-3
• Main Authors: Mikulics, M., Marso, M., Mayorga, I. Cámara, Güsten, R., Stanček, S., Kováč, P., Wu, S., Li, Xia, Khafizov, M., Sobolewski, R., Michael, E. A., Schieder, R., Wolter, M., Buca, D., Förster, A., Kordoš, P., Lüth, H.
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.2006983

We report on fabrication and measurement of photomixers based on nitrogen-ion-implanted GaAs. We used energies of 500 keV , 700 keV , and 880 keV to implant N + ions into GaAs substrates with an ion concentration of ∼ 3 × 10 12 cm − 2 . The resulting material exhibited 110 fs carrier lifetime due to implantation-induced defects. Our photomixers were fabricated as metal-semiconductor-metal devices, placed at the feed point of a broadband antenna. Optoelectronic measurements were performed in the wavelength range between 350 nm and 950 nm . In comparison to their counterparts (photomixers fabricated on low-temperature-grown GaAs) the N + -implanted GaAs photomixers exhibit improvements on both the output power and responsivity. A maximal responsivity of above 100 mA ∕ W was achieved and we did not observe any dependence of the mixer cut-off frequency on the bias voltage. These characteristics make N + -implanted GaAs the material of choice for efficient optoelectronic photomixers.