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 GaAs based resonant cavity enhanced 1.3 micron photodetector

High-speed photodetectors operating at 1.3 and 1.55 μm are important for long distance fiber optic based telecommunication applications. We fabricated GaAs based photodetectors operating at 1.3 μm that depend on internal photoemission as the absorption mechanism. Detectors using internal photoemission have usually very low quantum efficiency. We increased the quantum efficiency using resonant cavity enhancement effect. Resonant cavity enhancement effect also introduced wavelength selectivity which is very important for wavelength division multiplexing based communication systems. The top-illuminated Schottky photodiodes were fabricated by a microwave-compatible monolithic microfabrication process. The top metal layer serves as the top mirror of the Fabry-Perot cavity. Bottom mirror is composed of 15 pair AlAs/GaAs distributed Bragg reflector. We have used transfer matrix method to simulate the optical properties of the photodiodes. Our room temperature quantum efficiency measurement and simulation of our photodiodes at zero bias show that, we have achieved 9 fold enhancement in the quantum efficiency, with respect to a similar photodetector without a cavity. We also investigated the effect of reverse bias on quantum efficiency. Our devices are RC time constant limited with a predicted 3-dB bandwidth of 70 GHz

High-performance ITO-AlAs/GaAs based resonant cavity enhanced Schottky photodiodes

The fabrication of ITO (indium tin oxide)-AlAs-based resonant cavity enhanced Schottky photodiodes was examined. The device structure was designed to achieve a low-loss cavity around a 840 nm optical communication window. The layers were grown by molecular beam epitaxy on a GaAs substrate. Photoresponse measurements were carried out in 750-900 nm wavelength range using a tungsten-halogen projection lamp as the light source and single pass monochromator. Although the discrepancy between the experiment and theory was quite large, a nearly parallel enhancement of the initial efficiency values was observed as a function of the top distributed Bragg reflector pair

High-speed widely-tunable >90% quantum-efficiency resonant cavity enhanced p-i-n photodiodes

Widely-tunable high-speed resonant cavity enhanced p-i-n photodiodes were designed, fabricated and tested for operation around 820 nm. The structure was grown by solid-source MBE on GaAs substrates and features high-reflectivity Bragg mirrors made of quarter-wave Al0.20Ga0.80As/AlAs stacks. Photoresponse and photospectral measurements were carried out. The tuning of the resonance wavelength within the Bragg mirror's upper and lower edges was observed. Quantum efficiency greater than 90% was demonstrated

High-speed high-efficiency resonant cavity enhanced photodiodes

In this paper, we review our research efforts on RCE high-speed high-efficiency p-i-n and Schottky photodiodes. Using a microwave compatible planar fabrication process, we have designed and fabricated GaAs based RCE photodiodes. For RCE Schottky photodiodes, we have achieved a peak quantum efficiency of 50% along with a 3-dB bandwidth of 100 GHz. The tunability of the detectors via a recess etch is also demonstrated. For p-i-n type photodiodes, we have fabricated and tested widely tunable devices with near 100% quantum efficiencies, along with a 3-dB bandwidth of 50 GHz. Both of these results correspond to the fastest RCE photodetectors published in scientific literature

1.3 μm GaAs based resonant cavity enhanced Schottky barrier internal photoemission photodetector

GaAs based photodetectors operating at 1.3 μm that depend on internal photoemission as the absorption mechanism were fabricated. Quantum efficiency (QE) was increased using resonant cavity enhancement (RCE) effect

High-speed 1.3 μm GaAs internal photoemission resonant cavity enhanced photodetector

Photoresponse measurements were carried out in the 1100-1500 nm range by using a single-pass monochromator and a tungsten-halogen projection lamp as the light source. Further, high-speed measurements were made with an optical parametric oscillator (OPO). In general, the results correspond to the first high-speed internal photoemission photodetectors