Photomixers fabricated on nitrogen-ion-implanted GaAs

Abstract

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 ϳ3 ϫ 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 GaAs͒ 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.

Investigations of various cw terahertz photomixers

“…It means that the electron drift velocity in a LTG GaAs layer, from which the emitter is manufactured, does not saturate at these electric fields, most probably because of high defect density and small low-field mobility in the material. At the largest biases the power of generated THz signals has been reaching 0.35 µW, which corresponds to the optical-to-THz conversion efficiency of ∼2·10 −5 , comparable to the best values of this parameter known in the literature [11,12].…”

Semiconductor Diode Lasers for Terahertz Technology

“…This is the material most commonly used for photoconducting antennas. Alternatively, the defects in the semiconductor can be generated by ion bombardment [40][41][42]. In addition to the properties of the semiconductor, the geometry of the antenna electrodes is important for the antenna characteristics [43].…”

Annealing dynamics of As ion-implanted GaAs: As Ga antisite defect model

“…Although, studies on the properties of ion-implanted GaAs have been preformed, most studies were related to its carrier trap time, high mobility, and high resistivity. [17][18][19][20][21][22][23][24][25][26][27][28] In spite of these studies, however, the origin of the short carrier trap time, or the nature of the carrier trap states has not been cleared yet. This also means that the annealing dynamics of ion-implanted GaAs has not been understood yet.…”