| 1. |
- Zhao Ternehäll, Huan, 1982, et al.
(författare)
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Comparison of optical and structural quality of GaIn(N) As analog and digital quantum wells grown by molecular beam epitaxy
- 2008
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 0268-1242 .- 1361-6641. ; 23:12, s. 125002-
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Tidskriftsartikel (refereegranskat)abstract
- A set of Ga0.625In0.375(N) As single quantum well (QW) samples with the identical total amounts of Ga and In and QW thicknesses was designed and grown by both the analog and the digital methods using molecular beam epitaxy. The N exposure time in the GaInNAs samples was kept the same. The inter-band gap recombination in the analog and the digital InGaAs QWs appears in a similar transition energy range as a result of In segregation. Temperature-dependent photoluminescence (PL) measurements were performed on the GaInNAs samples. An S-shaped dependence of the transition energy on temperature was observed in the digital GaInNAs QWs but not in the analog GaInNAs QW. Post-growth rapid thermal annealing had remarkably different effects on the PL intensity: an increase for the analog InGaAs QW and for the analog and digital GaInNAs QWs, but a decrease for the digital InGaAs QW with increasing annealing temperature. The GaIn(N) As samples grown by the digital method showed weaker PL intensities and smaller wavelength blue-shifts than the similar samples grown by the analog method. Possible strain relaxation mechanisms are discussed.
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| 2. |
- Zhao Ternehäll, Huan, 1982, et al.
(författare)
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Growth and characterization of GaInNAs by molecular beam epitaxy using a nitrogen irradiation method
- 2009
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Ingår i: JOURNAL OF CRYSTAL GROWTH. - : Elsevier BV. - 0022-0248. ; 311:7, s. 1723-1727
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Tidskriftsartikel (refereegranskat)abstract
- We propose an innovative technique, making use of the In segregation effect, referred as the N irradiation method, to enhance In-N bonding and extend the emission wavelength of GaInNAs quantum wells (QWs). After the formation of a complete In floating layer, the growth is interrupted and N irradiation is initiated. The majority of N atoms are forced to bond with In atoms and their incorporation is regulated independently by the N exposure time and the As pressure. The effect of the N exposure time and As pressure on the N incorporation and the optical quality of GaInNAs QWs were investigated. Anomalous photoluminescence (PL) wavelength red shifts after rapid thermal annealing (RTA) were observed in the N-irradiated samples, whereas a normal GaInNAs sample revealed a blue shift. This method provides an alternative way to extend the emission wavelength of GaInNAs QWs with decent optical quality. We demonstrate light emission at 1546 nm from an 11-nm-thick QW, using this method and the PL intensity is similar to that of a 7-nm-thick GaInNAs QW grown at a reduced rate.
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| 3. |
- L.Q.Zhang,, et al.
(författare)
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Fabrication of novel unipolar nanodiodes in InAs/AlSb for microwave detection
- 2011
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Ingår i: Infrared, Millimeter and Terahertz Waves (IRMMW-THz), 2011 36th International Conference on. - 2162-2027. - 9781457705083 ; :2-7 Oct. 2011, s. 1-2
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Konferensbidrag (refereegranskat)abstract
- Abstract—We report on the fabrication of unipolar nanodiodes into an InAs/AlxGa1-xSb quantum-well heterostructure for room temperature microwave detection up to 110 GHz. Electron-beam lithography was combined with both dry- and wet-etching, and we explored the differences in the electric and detection parameters with the two methods.
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| 4. |
- Moschetti, Giuseppe, 1982, et al.
(författare)
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Anisotropic transport properties in InAs/AlSb heterostructures
- 2010
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 97:24, s. 3-
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the anisotropic transport behavior of InAs/AlSb heterostructures grown on a(001) InP substrate. An electrical analysis showed anisotropic sheet resistance Rsh and electronmobility μn in the two dimensional electron gas (2DEG). Hall measurements demonstrated anenhanced anisotropy in μn when cooled from room temperature to 2 K. High electron mobilitytransistors exhibited 27% higher maximum drain current IDS and 23% higher peak transconductancegm when oriented along the [1-10] direction. The anisotropic transport behavior in the 2DEG wascorrelated with an asymmetric dislocation pattern observed in the surface morphology and bycross-sectional microscopy analysis of the InAs/AlSb heterostructure.
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| 5. |
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| 6. |
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| 7. |
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| 8. |
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| 9. |
- Westlund, Andreas, 1985, et al.
(författare)
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Fabrication and DC characterization of InAs/AlSb self-switching diodes
- 2012
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Ingår i: Conference Proceedings - International Conference on Indium Phosphide and Related Materials. - 1092-8669. - 9781467317252 ; , s. 65-68
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Konferensbidrag (refereegranskat)abstract
- Fabrication and DC measurements of an InAs/AlSb self-switching diode (SSD), aimed for THz detection, is presented. An SSD with a channel width of 160 nm and a trench width of 240 nm was designed and fabricated in a process using an in situ passivation procedure of the oxidation-sensitive trench. Rectifying behavior was observed in the I-V characteristics. The device performance was relatively stable over a period of three months.
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| 10. |
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| 11. |
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| 12. |
- Baranowski, M, et al.
(författare)
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Contactless Electroreflectance, Photoluminescence and Time-Resolved Photoluminescence of GaInNAs Quantum Wells Obtained by the MBE Method with N-irradiation
- 2011
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 26:4, s. 045012-
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Tidskriftsartikel (refereegranskat)abstract
- The optical properties of GaInNAs quantum wells (QW) grown by molecular beam epitaxywith and without N-irradiation (i.e. grown by the classical method) were investigated by thecontactless electroreflectance (CER), temperature-dependent photoluminescence (PL) andtime-resolved PL (TRPL). From CER measurements it was concluded that one type ofnitrogen nearest-neighbor environment (In-rich environment) is dominant for GaInNAs QWsgrown with N-irradiation whereas various nitrogen environments are present for the referenceGaInNAs QW (i.e. the sample obtained by the classical method). PL and TRPL measurementsclearly show that the optical properties of GaInNAs QWs are affected mainly by the amount ofthe incorporated nitride atoms. It was observed that the PL decay time decreased from ∼200to ∼40 ps when the nitrogen concentration is increased from 0.8 to 2.2%. In addition, thepresence of As flux during N-irradiation reduces the amount of the incorporated nitrogen andsimultaneously improves the optical quality of GaInNAs QWs (i.e. it weakens the carrierlocalization at low temperatures and improves the quantum efficiency of PL).
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| 13. |
- Chen, Xiren, et al.
(författare)
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Bi-Induced Electron Concentration Enhancement Being Responsible for Photoluminescence Blueshift and Broadening in InAs Films
- 2019
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Ingår i: Physica Status Solidi (B): Basic Research. - : Wiley. - 1521-3951 .- 0370-1972. ; 256:5
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Tidskriftsartikel (refereegranskat)abstract
- Photoluminescence (PL) study is conducted on InAs films molecular beam epitaxially grown on GaAs substrates with different Bi flux levels. A PL peak blueshift accompanied by linewidth broadening is found with the increase of Bi/As flux ratio, in contrast to the common Bi isoelectronic incorporation or surfactant effect. It is, with detailed lineshape analysis and the evidence of PL peak splitting in a magnetic filed, attributed to the electron concentration enhancement induced by Bi flux. The electron concentration in InAs film is evaluated, which is about 5-fold enhanced as Bi/As flux ratio rises up from 0 to 1x10(-3). The temperature dependence of the PL spectrum indicates that the carrier redistribution augments while the carrier-phonon Frohlich scattering weakens in InAs films with high Bi/As flux ratios. These findings reveal a novel Bi effect of electron concentration enhancement, and contribute to the basic knowledge of Bi in III-V semiconductors.
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| 14. |
- Drakinskiy, Vladimir, 1977, et al.
(författare)
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Status and Progress of Schottky Technology Development for SWI and ISMAR
- 2015
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Ingår i: 26th International Symposium on Space Terahertz Technology, ISSTT 2015; Cambridge; United States; 16 March 2015 through 18 March 2015. ; , s. P-6
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Konferensbidrag (refereegranskat)abstract
- We present the progress of the technological development of a full e-beam based monolithically integrated Schottky diode process applicable for sub-millimetre wave multipliers and mixers. The process has been employed in a number of demonstrators showing state-of-the-art performance.
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| 15. |
- Drakinskiy, Vladimir, 1977, et al.
(författare)
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Terahertz GaAs Schottky diode mixer and multiplier MIC’s based on e-beam technology
- 2013
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Ingår i: Conference Proceedings - International Conference on Indium Phosphide and Related Materials. - 1092-8669. - 9781467361316
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Konferensbidrag (refereegranskat)abstract
- We present the progress of the technological development of a full e-beam based monolithically integrated Schottky diode process applicable for sub-millimetre wave multipliers and mixers. Evaluation of the process has been done in a number of demonstrators showing state-of-the-art performance, including various multiplier circuits up to 200 GHz with a measured flange efficiency of above 35%, as well as heterodyne receiver front-end modules operating at 340 GHz and 557 GHz with a measured receiver DSB noise temperature of below 700 K and 1300 K respectively.
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| 16. |
- Fadaly, Elham, et al.
(författare)
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Production of nano-holes patten on Si(111) by colloidal lithography for growth of InAs nanowires
- 2015
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Ingår i: 15th International Conference on Nanotechnology.
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Konferensbidrag (refereegranskat)abstract
- Colloidal lithography is a simple, versatile and low-cost technique that can be used to pattern diverse nanostructures on a wafer scale. In this work, colloidal lithography utilizing polystyrene nanoparticles as a lift-off mask was used to produce nanohole patterns on Si (111) substrates. The hole size, which is determined by the size of the polystyrene particles, can be well controlled by oxygen plasma shrinking. Using this technique, we were able to obtain nanohole pattern with feature size down to 50 nm, which is close to the limit that conventional lithographic techniques can reach, in a time-efficient and cost effective manner. InAs nanowires were successfully grown on the patterned substrates using molecular beam epitaxy.
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| 17. |
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| 18. |
- Hammar, Arvid, 1986, et al.
(författare)
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A 600 GHz Orthomode Transducer based on a Waveguide Integrated Wire Grid Polarizer
- 2012
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Ingår i: TWENTY-THIRD INTERNATIONAL SYMPOSIUM ON SPACE TERAHERTZ TECHNOLOGY (ISSTT2012).
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Konferensbidrag (refereegranskat)abstract
- Abstract — We present a new type of orthomode transducer (OMT), involving the integration of a quasi-optical component, namely a wire grid polarizer (WGP), with an E-plane probe transition, in a waveguide topology. The goal has been to create a lightweight and compact device for waveguide integration, capable of covering all frequency channels to be used by the FIRE instrument¤.The design consists of a metallic split block, in which a quadratic waveguide supporting the two fundamental modes of propagation (TE10 and TE01), is formed using regular CNC milling. Just as its quasi-optical counterpart, i.e. a free standing WGP, a waveguide integrated WGP insert is used to separate the two orthogonal TE modes, which are either reflected or transmitted (depending on polarization). A planar E-plane waveguide probe transition realized on a GaAs membrane is used inside a square waveguide to extract the reflected mode without affecting the transmitted mode. For a first proof of concept the OMT has been designed for the possibility of full characterization and therefore the transmitted mode is guided through a stepped impedance transformer to a standard rectangular waveguide interface, while a second E-plane probe transition to a rectangular waveguide, is used for the reflected mode. Simulations carried out using Ansoft HFSS show that the OMT design can be made relatively broadband (currently about ~14% with a return loss better than 15 dBs) and with cross-polarizations better than 30 dB. The probe and WGP can be manufactured using high precision photolithography or E-beam lithography making it scalable to both lower and higher frequency bands. Assembling an OMT of this type involves mounting of small membrane structures (
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| 19. |
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| 20. |
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| 21. |
- Malko, Aleksandra, 1984, et al.
(författare)
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Heterogeneous Integration of Terahertz Diode Circuits
- 2016
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Ingår i: 2015 Asia-Pacific Microwave Conference. ; 1
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Konferensbidrag (refereegranskat)abstract
- We present an overview of the research made on integrated diode circuits for terahertz applications. This includes progress on heterogeneous integration of heterostructure barrier varactor multipliers and Schottky diode mixers on silicon substrate. The described technology uses silicon-on-insulator (SOI) substrates, for which accurate and well defined substrate thickness for the microstrip circuitry is obtained.
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| 22. |
- Malko, Aleksandra, 1984, et al.
(författare)
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Heterostructure integrated HBV-based frequency quintupler for 500 GHz
- 2014
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Ingår i: 38th Workshops on Compound Semiconductors Devices and Integrated Circuits. ; , s. 11 - 12
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Konferensbidrag (refereegranskat)abstract
- We present a heterogeneous integrated frequency quintupler based on heterostructure barrier varactor (HBV) operating in the frequency range from 440 GHz to 490 GHz. The HBV material structure was transferred onto silicon on insulator (SOI) using low temperature plasma activated wafer bonding. The top layer of the SOI has a high resistivity (10,000 Ωcm) and is 20 μm thick. Thus, not only minimized substrate losses, but also an accurate and uniform thickness of the quintupler chip is obtained. The maximum output power for this device is 6 mW at 472.5 GHz.
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| 23. |
- Malko, Aleksandra, 1984, et al.
(författare)
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Thermal Analysis of III-V HBV Diode Structures on InP, GaAs, Silicon and Diamond Substrates
- 2013
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Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. ; , s. 1-2
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Konferensbidrag (refereegranskat)abstract
- Thermal analysis of In0.53Ga0.47As and GaAs Heterostructure Barrier Varactors diodes on InP, GaAs, silicon and diamond substrates are presented. The physical dimensions of the analysed structures correspond to the dimensions of a high power integrated HBV frequency multipliers for W-band (70 – 110 GHz). It is shown that material transfer to substrates with higher thermal conductivity will reduce thermal resistance by 21 % and approximately 50 % for In0.53Ga0.47As and GaAs HBVs, respectively. Thus, an enhanced thermal handling capability of the HBV multiplier sources can be obtained.
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| 24. |
- Malko, Aleksandra, 1984, et al.
(författare)
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Wafer bondig for integrated III-V frequency multipliers on silicon
- 2013
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Ingår i: Conference on Wafer Bonding for Microsystems 3D- and Wafer Level Integration. ; , s. 75 - 76
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Konferensbidrag (refereegranskat)abstract
- In this paper low temperature (LT) plasma assisted wafer bonding for integration of an InGaAs/InAlAs/AlAs epitaxial strucutre is utilised to fabricate a heterostrucutre barrier varactor (HBV). Due to its nonlinear properties the HBV generates only odd harmonics of the input signal, thus the device can be used as a frequency multiplier. The silicon serves as the substrate for the microstrip circuitry.
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| 25. |
- Neumaier, Philipp, 1984, et al.
(författare)
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Molecular Spectroscopy With a Compact 557-GHz Heterodyne Receiver
- 2014
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 4:4, s. 469-478
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Tidskriftsartikel (refereegranskat)abstract
- We report on a heterodyne terahertz spectrometer based on a fully integrated 557-GHz receiver and a digital fast Fourier transform spectrometer. The receiver consists of a chain of multipliers and power amplifiers, followed by a heterostructure barrier varactor tripler that subharmonically pumps a membrane GaAs Schottky diode mixer. All sub-components are newly developed and optimized with regard to the overall receiver performance such as noise temperature, power consumption, weight and physical size. The receiver works at room temperature, has a double sideband noise temperature as low as 2000 K at a maximum power consumption of 4.5 W with an Allan time of 10 s and a sideband gain ratio of 0.52. The performance of the spectrometer is demonstrated by absorption spectroscopy of H2O and CH3OH with an instantaneous bandwidth of 1.5 GHz and a resolution of 183 kHz. Several pressure broadening parameters of methanol absorption lines were determined, that agree with other published data. Using the experimentally determined molecular parameters the CH3OH absorption spectrum could be modeled with very high precision.
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