devices fabricated at the scaling limits of conventional technology must either contend with quantum-mechanical tunneling as a parasitic effect or incorporate tunneling into the device function. Taking the latter appr...
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devices fabricated at the scaling limits of conventional technology must either contend with quantum-mechanical tunneling as a parasitic effect or incorporate tunneling into the device function. Taking the latter approach, the phenomenon of resonant tunneling between epitaxially-grown double-barrier heterostructures shows significant promise for extending integrated circuit performance both before and beyond the post-shrink era. Recent progress in this technology is reviewed.
A novel, high sensitivity photodetector which combines a p-i-n diode and a modulation doped field effect transistor (MODFET) in a single device is reported for the first time. There are two possible modes of operation...
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ISBN:
(纸本)0780324420
A novel, high sensitivity photodetector which combines a p-i-n diode and a modulation doped field effect transistor (MODFET) in a single device is reported for the first time. There are two possible modes of operation of the device, a vertical p-i-n mode and a lateral MODFET mode. The device exhibits a high responsivity of approximately 95 A/W in the MODFET mode which is approximately 6000 times that in the p-i-n mode. The device also has significant photo-response in the GaAs sub-bandgap region arising from the arsenic clusters and/or the traps present in the low-temperature grown GaAs (LT-GaAs) layer.
The results of an experimental and theoretical investigation into the present limitations on the overall small signal direct modulation bandwidth in semiconductor lasers are presented. The influences of the optical gu...
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The results of an experimental and theoretical investigation into the present limitations on the overall small signal direct modulation bandwidth in semiconductor lasers are presented. The influences of the optical guide and cavity design are examined.
Monolithic integration of lasers and photodetectors with electronic circuits promises higher bandwidth, improved manufacturability, smaller size, lower power and hence lower costs. This paper reviews the activities of...
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Monolithic integration of lasers and photodetectors with electronic circuits promises higher bandwidth, improved manufacturability, smaller size, lower power and hence lower costs. This paper reviews the activities of the Fraunhofer IAF on optoelectronic integrated circuits (OEICs) for serial and parallel optical links.
We have developed a novel low cost nanogrowth technology for the fabrication of periodic arrays of semiconductor quantum dots on silicon with good device size uniformity. The technique utilizes material growth on a pr...
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We have developed a novel low cost nanogrowth technology for the fabrication of periodic arrays of semiconductor quantum dots on silicon with good device size uniformity. The technique utilizes material growth on a preformed template formed by electrochemical etching of aluminum on silicon. The template contains a periodic array of pores in which the semiconductor material is synthesized. The technique is inexpensive, reliable, suitable for the fabrication of a variety of semiconductors, VLSI compatible and has the potential for integration of quantum dot devices with silicon integrated circuits.
In [111]-oriented InGaAs/GaAs multiple quantum wells and superlattices, the field in the wells, barriers, and the average electric field, are deduced using simple analytical expressions. The influence of the design pa...
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ISBN:
(纸本)0780324420
In [111]-oriented InGaAs/GaAs multiple quantum wells and superlattices, the field in the wells, barriers, and the average electric field, are deduced using simple analytical expressions. The influence of the design parameters on the conduction-band profile and optoelectronics properties of strained piezoelectric p-i-n diodes is presented. In samples with negative average electric field, transient photocurrent response and photocapacitance-voltage characteristics clearly reveal that carriers accumulate at the extremes of the active region, giving rise to a long-range screening effect of the field in the wells. Coupled quantum wells and piezoelectric superlattices have been studied by photocapacitance techniques, and the revealed features were explained as due to carrier sequential tunneling and accumulation processes.
We demonstrate a low cost, manufacturable method for fabricating microwave elements on lossy substrates as required for Si-based devices. These microwave elements require a ground-plane on the surface of the Si substr...
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We demonstrate a low cost, manufacturable method for fabricating microwave elements on lossy substrates as required for Si-based devices. These microwave elements require a ground-plane on the surface of the Si substrate to shield the lossy dielectric below and use a 13 μm thick layer of benzocyclobutene (BCB) for wave propagation. The performance of the transmission lines and MMICs thus fabricated are comparable to their GaAs counterparts.
The fundamental response of transit time photodetectors with picosecond response times has been analyzed through Monte Carlo simulation of MSM photodiodes. The fundamental response was found to consist of three compon...
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ISBN:
(纸本)0780324420
The fundamental response of transit time photodetectors with picosecond response times has been analyzed through Monte Carlo simulation of MSM photodiodes. The fundamental response was found to consist of three components: a fast initial peak due to velocity overshoot in the /spl Gamma/ valley electrons, a slow secondary steady state electron response, and a slow steady state hole response. The relative magnitude of the two electron responses was found to be extremely sensitive to the device length, the electric field, and the energy of the exciting photons, such that, for a given device length and photon energy there is an optimal electric field for which the electron transit time is minimized. The hole transit time was observed to decrease monotonically with increasing electric field, thus making it difficult to optimize the electron and hole responses simultaneously. Accounting for the hole response was found to increase the magnitude of the optimal field. The detector response was also observed to degrade significantly as the energy of the exciting photons was increased.
For several years it has been recognized that the single band effective mass model is insufficient to simulate quantum transport in material systems which are currently under investigation. This has prompted a growing...
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For several years it has been recognized that the single band effective mass model is insufficient to simulate quantum transport in material systems which are currently under investigation. This has prompted a growing effort on the part of theorists to include realistic bandstructures in quantum transport simulations. However, full bandstructure current-voltage calculations have proven to be numerically prohibitive. In this work we introduce an efficient technique to calculate current-voltage characteristics for quantum devices using tight-binding bandstructure models.
Quasi-optics offers an attractive means of creating moderate-power solid-state millimeter-wave transmitters. This paper presents the development of a 28 GHz oscillator, including an InP power HEMT and integrated with ...
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Quasi-optics offers an attractive means of creating moderate-power solid-state millimeter-wave transmitters. This paper presents the development of a 28 GHz oscillator, including an InP power HEMT and integrated with a planar, endfire antenna, which is used in testing metal reflectors designed for generating omni-directional patterns for point-to-multipoint distribution. Results of this work give insight into tailoring the reflectors for omni-directional active arrays.
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