72 research outputs found
High speed and high efficiency infrared photodetectors
Cataloged from PDF version of article.The increasing demand for telecommunication systems resulted in production
of high performance components. Photodetectors are essential components of
optoelectronic integrated circuits and fiber optic communication systems. We
successfully used resonant cavity enhancement technique to improve InGaAs
based p-i-n photodetectors. The detectors had 66% peak quantum efficiency at
1572 nm which showed 3 fold increases with respect to similar photodetector
without resonant cavity. The detectors had 28 GHz 3-dB bandwidth at the same
time. The bandwidth efficiency product for these detectors was 18.5 GHz, which is
one of the best results for InGaAs based vertical photodetector.
The interest in high speed photodetectors is not limited to fiber optic networks.
In the recent years, data communication through the air has become popular due to ease of installation and flexibility of these systems. Although the current systems
still operate at 840 nm or 1550 nm wavelengths, the advantage of mid-infrared
wavelengths will result in the production of high speed lasers and photodetectors.
InSb based p-i-n type photodetectors were fabricated and tested for the operation
in the mid-infrared (3 to 5 µm) wavelength range. The epitaxial layers were grown
on semi-insulating GaAs substrate by molecular beam epitaxy method. The
detectors had low dark noise and high differential resistance around zero bias.
Also the responsivity measurements showed 49% quantum efficiency. The
detectivity was measured as 7.98×109
cm Hz1/2/W for 60 µm diameter detectors.
Finally the high speed measurements showed 8.5 and 6.0 GHz bandwidth for 30
µm and 60 µm diameter detectors, respectively.Kimukin, İbrahimPh.D
Long wavelength GaAs based hot electron photoemission detectors
Ankara : The Department of Physics and the Institute of Engineering and Science of Bilkent Univ. , 1999.Thesis (Master's) -- Bilkent University, 1999.Includes bibliographical references leaves 68-62The increasing rate of telecommunication alters both science and technology, and
demands high performance components. Photo detectors are essential components
of optoelectronic integrated circuits and fiber optic communication systems. A new
family of photodetectors offer high performance along with wavelength selectivity:
resonant cavity enhanced (RCE) photodetectors.
In this thesis, we present our efforts for design, fabrication and characterization
of GaAs/AIGaAs based Schottky photodetectors operating within the first (850 nm)
and second (1300 nm) optical communication windows. Epitaxial wafers are designed
using transfer matrix method based simulation and are grown with molecular beam
epitaxy. The photodetector operating at 840 nm was designed with indium tin oxide
(IT O ) Schottky layer for high quantum efficiency. The second photodetector is based
on internal photoemission, and is compatible with advanced GaAs process technology.
Our aim with this design is high speed operation at the second optical communication
window. We measured 20 GHz 3-dB bandwidth with 60% quantum efficiency at 840
nm. We expect 50 GHz 3-dB bandwidth with 0.05% quantum efficiency at 1310 nmKimukin, İbrahimM.S
High-speed visible-blind GaN-based indium-tin-oxide Schottky photodiodes
Cataloged from PDF version of article.We have fabricated GaN-based high-speed ultraviolet Schottkyphotodiodes using indium–tin–oxide (ITO) Schottky contacts. Before devicefabrication, the optical transparency of thin ITO films in the visible-blind spectrum was characterized via transmission and reflection measurements. The devices were fabricated on n−/n+GaN epitaxial layers using a microwave compatible fabrication process. Our ITO Schottkyphotodiode samples exhibited a maximum quantum efficiency of 47% around 325 nm. Time-based pulse-response measurements were done at 359 nm. The fabricateddevices exhibited a rise time of 13 ps and a pulse width of 60 ps.
© 2001 American Institute of Physic
High-speed solar-blind photodetectors with indium-tin-oxide Schottky Contacts
Cataloged from PDF version of article.We report AlGaN/GaN-based high-speed solar-blind photodetectors with indium-tin-oxide Schottky contacts. Current-voltage, spectral responsivity, and high-frequency response characterizations were performed on the fabricated Schottky photodiodes. Low dark currents of <1 pA at 20 V reverse bias and breakdown voltages larger than 40 V were obtained. A maximum responsivity of 44 mA/W at 263 nm was measured, corresponding to an external quantum efficiency of 21%. True solar-blind detection was ensured with a cutoff wavelength of 274 nm. Time-based high-frequency measurements at 267 nm resulted in pulse responses with rise times and pulse-widths as short as 13 and 190 ps, respectively. The corresponding 3-dB bandwidth was calculated as 1.10 GHz. (C) 2003 American Institute of Physics
Solar-blind AlGaN-based Schottky photodiodes with low noise and high detectivity
Cataloged from PDF version of article.We report on the design, fabrication, and characterization of solar-blind Schottky photodiodes with low noise and high detectivity. The devices were fabricated on n-/n+ AlGaN/GaN heterostructures using a microwave compatible fabrication process. True solar-blind operation with a cutoff wavelength of similar to274 nm was achieved with Al(x)Ga(1-x)N (x=0.38) absorption layer. The solar-blind detectors exhibited <1.8 nA/cm(2) dark current density in the 0-25 V reverse bias regime, and a maximum quantum efficiency of 42% around 267 nm. The photovoltaic detectivity of the devices were in excess of 2.6x10(12) cm Hz(1/2)/W, and the detector noise was 1/f limited with a noise power density less than 3x10(-29) A(2)/Hz at 10 kHz. (C) 2002 American Institute of Physics
High-Speed InSb Photodetectors on GaAs for Mid-IR Applications
Cataloged from PDF version of article.We report p-i-n type InSb-based high-speed photodetectors grown on GaAs substrate. Electrical and optical properties of photodetectors with active areas ranging from 7.06 x 10(-6) cm(2) to 2.25 x 10(-4) cm(2) measured at 77 K and room temperature. Detectors had high zero-bias differential resistances, and the differential resistance area product was 4.5 Omega cm(2). At 77 K, spectral measurements yielded high responsivity between 3 and 5 mum with the cutoff wavelength of 5.33 mum. The maximum responsivity for 80-mum diameter detectors was 1.00x10(5) V/W at 4.35 mum while the detectivity was 3.41x10(9) cm Hz(1/2) /W. High-speed measurements were done at room temperature. An optical parametric oscillator was used to generate picosecond full-width at half-maximum pulses at 2.5 mum with the pump at 780 nm. 30-mum diameter photodetectors yielded 3-dB bandwidth of 8.5 GHz at 2.5 V bias
Solar-blind A1GaN-based p-i-n photodiodes with low dark current and high detectivity
We report solar-blind AlxGal1-xN-based heterojunction p-i-n photodiodes with low dark current and high detectivity. After the p+ GaN cap layer was recess etched, measured dark current was below 3 fA for reverse bias values up to 6 V. The device responsivity increased with reverse bias and reached 0.11 A/W at 261 nm under 10-V reverse bias. The detectors exhibited a cutoff around 283 nm, and a visible rejection of four orders of magnitude at zero bias. Low dark current values led to a high differential resistance of 9.52 × 1015 Ω. The thermally limited detectivity of the devices was calculated as 4.9 × 1014 cm · Hz1/2W-1. © 2004 IEEE
InGaAs-based high-performance p-i-n photodiodes
Cataloged from PDF version of article.In this letter, we have designed, fabricated, and
characterized high-speed and high-efficiency InGaAs-based p-i-n
photodetectors with a resonant cavity enhanced structure. The
devices were fabricated by a microwave-compatible process. By
using a postprocess recess etch, we tuned the resonance wavelength
from 1605 to 1558 nm while keeping the peak efficiencies above
60%. The maximum quantum efficiency was 66% at 1572 nm
which was in good agreement with our theoretical calculations.
The photodiode had a linear response up to 6-mW optical power,
where we obtained 5-mA photocurrent at 3-V reverse bias. The
photodetector had a temporal response of 16 ps at 7-V bias. After
system response deconvolution, the 3-dB bandwidth of the device
was 31 GHz, which corresponds to a bandwidth-efficiency product
of 20 GHz
High-speed GaAs-based resonant-cavity-enhanced 1.3 μm photodetector
Cataloged from PDF version of article.We report GaAs-based high-speed, resonant-cavity-enhanced, Schottky barrier internal photoemissionphotodiodes operating at 1.3 μm. The devices were fabricated by using a microwave-compatible fabrication process. Resonance of the cavity was tuned to 1.3 μm and a nine-fold enhancement was achieved in quantum efficiency. The photodiode had an experimental setup limited temporal response of 16 ps, corresponding to a 3 dB bandwidth of 20 GHz.
© 2000 American Institute of Physic
Ultrafast and highly efficient resonant cavity enhanced photodiodes
In this talk, we will review our research efforts on resonant cavity enhanced (RCE) high-speed high-efficiency photodiodes (PDs) operating in the 1st and 3rd optical communication windows. Using a microwave compatible planar fabrication process, we have designed and fabricated GaAs and InGaAs based RCE photodiodes. For RCE GaAs Schottky type photodiodes, we have achieved peak quantum efficiencies of 50% and 75% with semi-transparent (Au) and transparent (indium-tin-oxide) Schottky layers respectively. Along with 3-dB bandwidths of 50 and 60 GHz, these devices exhibit bandwidth-efficiency (BWE) products of 25 GHz and 45 GHz respectively. By using a postprocess recess etch, we tuned the resonance wavelength of an RCE InGaAs PD from 1605 to 1558 nm while keeping the peak efficiencies above 60%. The maximum quantum efficiency was 66% at 1572 nm which was in good agreement with our theoretical calculations. The photodiode had a linear response up to 6 mW optical power, where we obtained 5 mA photocurrent at 3 V reverse bias. The photodetector had a temporal response of 16 psec at 7 V bias. After system response deconvolution, the 3-dB bandwidth of the device was 31 GHz, which corresponds to a bandwidth-efficiency product of 20 GHz
- …