Monolithic Integration of Ultrafast Photodetector and MESFET in the GaN Material System

in IEEE Photonics Technology Letters (2011), 23(17), 1189-1191

We have fabricated and characterized ultrafast metal–semiconductor–metal (MSM) photodetectors integrated with metal–semiconductor–field-effect-transistors (MESFETs) integrated in coplanar strip lines in ... [more ▼]

We have fabricated and characterized ultrafast metal–semiconductor–metal (MSM) photodetectors integrated with metal–semiconductor–field-effect-transistors (MESFETs) integrated in coplanar strip lines in the GaN/AlN/SiC material system. We recorded electrical transients of the single photodetector as short as 0.9 ps wide by optoelectric pump–probe measurements using 360-nm-wavelength and 100-fs-duration laser pulses. Electric photoresponse transients of the photodetector with 6-mV peak amplitude were amplified by the MESFET, resulting in 4-ps-wide and 35-mV peak amplitude signals. This monolithically integrated optoelectronic circuit is presented as a potential candidate for high-speed ultraviolet optoelectronics [less ▲]

Sensitivity enhancement of metal-semiconductor-metal photodetectors on low-temperature-grown GaAs using alloyed contacts

in IEEE Photonics Technology Letters (2008), 20(12), 1054-1056

We have fabricated and characterized metal–semiconductor–metal (MSM) photodetectors based on lowtemperature-grown GaAs with alloyed (i.e., ohmic-type) contacts. The annealed contacts optimize the electric ... [more ▼]

We have fabricated and characterized metal–semiconductor–metal (MSM) photodetectors based on lowtemperature-grown GaAs with alloyed (i.e., ohmic-type) contacts. The annealed contacts optimize the electric field distribution inside the photodetector structure which results in an up-to-200% responsivity increase of the devices, compared to conventional MSM detectors with standard nonalloyed (Schottky-type) metallization fabricated on identical material. The improved MSM device with alloyed contacts shows more than three times larger output amplitude at illumination with a 100-fs Ti : sapphire laser, compared to the nonalloyed devices, without degradation of detector speed. [less ▲]

Ultrafast Low-Temperature-Grown Epitaxial GaAs Photodetectors Transferred on Flexible Plastic Substrates

in IEEE Photonics Technology Letters (2005), 17(8), 1725-1727

We demonstrate low-temperature (LT)-grown GaAs photodetectors transferred on flexible polyethylene terephthalate (PET) plastic substrates. The LT-GaAs layer was patterned into 20 20 m2 chips, which after ... [more ▼]

We demonstrate low-temperature (LT)-grown GaAs photodetectors transferred on flexible polyethylene terephthalate (PET) plastic substrates. The LT-GaAs layer was patterned into 20 20 m2 chips, which after placing on the PET substrates were integrated with coplanar strip transmission lines. The devices exhibit low dark currents ( 2 10 8 A), subpicosecond photoresponse time, and signal amplitudes up to 0.9 V at the bias voltage of 80 V and under laser beam excitation power of 8 mW at 810-nm wavelength. At the highest bias ( 80 V) level, an increase of the response time (up to 1.3 ps) was observed and attributed to the influence of heating effects due to low thermal conductivity of PET. Our LT-GaAs-on-PET photodetectors withstand hundredfold mechanical bending of the substrate and are intended for applications in hybrid optoelectronic circuits fabricated on noncrystalline substrates, in terahertz imaging, and in biology-related current-excitation tests. [less ▲]

An InAlAs-InGaAs OPFET with Responsivity Above 200 A/W at 1.3 µm Wavelength

in IEEE Photonics Technology Letters (1999), 11

The optoelectronic dc and RF behavior of an InAlAs–InGaAs optically controlled field-effect transistor based on a high electron mobility transistor layer structure is investigated at 1.3- um wavelength ... [more ▼]

The optoelectronic dc and RF behavior of an InAlAs–InGaAs optically controlled field-effect transistor based on a high electron mobility transistor layer structure is investigated at 1.3- um wavelength light. The device is backside-illuminated to increase the responsivity. A transistor with 0.3-u m gate length and an active area of 50 x 50 u m2 exhibits a responsivity of 235 A/W, at 11- W incident optical power. The photoconductive response is higher than for an metal–semiconductor–metal photodetector with the same InGaAs absorption layer thickness up to 10 GHz. [less ▲]