| 1. |
- Junesand, Carl, et al.
(författare)
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Defect reduction in heteroepitaxial InP on Si by epitaxial lateral overgrowth
- 2014
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Ingår i: Materials Express. - : American Scientific Publishers. - 2158-5849 .- 2158-5857. ; 4:1, s. 41-53
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Tidskriftsartikel (refereegranskat)abstract
- Epitaxial lateral overgrowth of InP has been grown by hydride vapor phase epitaxy on Si substrates with a thin seed layer of InP masked with SiO2. Openings in the form of multiple parallel lines as well as mesh patterns from which growth occurred were etched in the SiO2 mask and the effect of different growth conditions in terms of V/III ratio and growth temperature on defects such as threading dislocations and stacking faults in the grown layers was investigated. The samples were characterized by cathodoluminescence and by transmission electron microscopy. The results show that the cause for threading dislocations present in the overgrown layers is the formation of new dislocations, attributed to coalescence of merging growth fronts, possibly accompanied by the propagation of pre-existing dislocations through the mask openings. Stacking faults were also pre-existing in the seed layer and propagated to some extent, but the most important reason for stacking faults in the overgrown layers was concluded to be formation of new faults early during growth. The formation mechanism could not be unambiguously determined, but of several mechanisms considered, incorrect deposition due to distorted bonds along overgrowth island edges was found to be in best agreement with observations.
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| 2. |
- Metaferia, Wondwosen, 1980-, et al.
(författare)
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High quality InP nanopyramidal frusta on Si
- 2014
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Ingår i: CrystEngComm. - : Royal Society of Chemistry (RSC). - 1466-8033. ; 16:21, s. 4624-4632
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Tidskriftsartikel (refereegranskat)abstract
- Nanosized octagonal pyramidal frusta of indium phosphide were selectively grown at circular hole openings on a silicon dioxide mask deposited on indium phosphide and indium phosphide pre-coated silicon substrates. The eight facets of the frusta were determined to be {111} and {110} truncated by a top (100) facet. The size of the top flat surface can be controlled by the diameter of the openings in the mask and the separation between them. The limited height of the frusta is attributed to kinetically controlled selective growth on the (100) top surface. Independent analyses with photoluminescence, cathodoluminescence and scanning spreading resistance measurements confirm certain doping enrichment in the frustum facets. This is understood to be due to crystallographic orientation dependent dopant incorporation. The blue shift from the respective spectra is the result of this enrichment exhibiting the Burstein-Moss effect. Very bright panchromatic cathodoluminescence images indicate that the top surfaces of the frusta are free from dislocations. The good optical and morphological quality of the nanopyramidal frusta indicates that the fabrication method is very attractive for the growth of site-, shape-, and number-controlled semiconductor quantum dot structures on silicon for nanophotonic applications.
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| 3. |
- Kataria, Himanshu, et al.
(författare)
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Carrier-transport, optical and structural properties of large area ELOG InP on Si using conventional optical lithography
- 2013
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Ingår i: 2013 International Conference on Indium Phosphide and Related Materials (IPRM). - : IEEE conference proceedings. - 9781467361309 - 9781467361316 ; , s. 6562592-
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Konferensbidrag (refereegranskat)abstract
- We present the carrier-transport, optical and structural properties of InP deposited on Si by Epitaxial Lateral Overgrowth (ELOG) in a Low Pressure-Hydride Vapor phase epitaxy (LP-HVPE). Hall measurements, micro photoluminescence (μ-PL) and X-ray diffraction (XRD) were used to study the above-mentioned respective properties at room temperature. It is the first time that electrical properties of ELOG InP on Si are studied by Hall measurements. Prior to ELOG, etching of patterned silicon dioxide (SiO2) mask leading to a high aspect ratio, i. e. mask thickness to opening width >2 was optimized to eliminate defect propagation even above the opening. Dense high aspect ratio structures were fabricated in SiO2 to obtain ELOG InP on Si, coalesced over large area, making it feasible to perform Hall measurements. We examine this method and study Hall mobility, strain and optical quality of large area ELOG InP on Si.
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| 4. |
- Kataria, Himanshu, et al.
(författare)
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Monolithic integration of InP based structures on silicon for optical interconnects
- 2014
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Ingår i: 2014 ECS and SMEQ Joint International Meeting. - : The Electrochemical Society. ; , s. 523-531
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Konferensbidrag (refereegranskat)abstract
- Monolithic integration of InP based structures on Si for optical interconnects is presented. Different strategies are demonstrated to achieve requisite InP platform on Si. In the first strategy, defect free isolated areas of epitaxially and laterally overgrown InP are obtained on Si and the InGaAsP based quantum wells directly grown on these templates have shown high material quality with uniform interfaces. In the second strategy, selective area growth is exploited to achieve InP nano pyramids on Si which can be used for the growth of quantum dot structures. In the third and the final strategy, a method is presented to achieve direct interface between InP and Si using corrugated epitaxial lateral overgrowth.
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| 5. |
- Metaferia, Wondwosen, et al.
(författare)
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Demonstration of a quick process to achieve buried heterostructure quantum cascade laser leading to high power and wall plug efficiency
- 2014
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Ingår i: Optical Engineering. - : SPIE-Intl Soc Optical Eng. - 0091-3286 .- 1560-2303. ; 53:8, s. 087104-
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Tidskriftsartikel (refereegranskat)abstract
- Together with the optimal basic design, buried heterostructure quantum cascade laser (BH-QCL) with semi-insulating regrowth offers a unique possibility to achieve an effective thermal dissipation and lateral single mode. We demonstrate here the realization of BH-QCLs with a single-step regrowth of highly resistive (>1 x 10(8) ohm . cm) semi-insulating InP: Fe in <45 min for the first time in a flexible hydride vapor phase epitaxy process for burying ridges etched down to 10 to 15 mu m depth, both with and without mask overhang. The fabricated BH-QCLs emitting at similar to 4.7 and similar to 5.5 mu m were characterized. 2-mm-long 5.5-mu m lasers with a ridge width of 17 to 22 mu m, regrown with mask overhang, exhibited no leakage current. Large width and high doping in the structure did not permit high current density for continuous wave (CW) operation. 5-mm-long 4.7-mu m BH-QCLs of ridge widths varying from 6 to 14 mu m regrown without mu mask overhang, besides being spatially monomode, TM00, exhibited wall plug efficiency (WPE) of similar to 8 to 9% with an output power of 1.5 to 2.5 W at room temperature and under CW operation. Thus, we demonstrate a quick, flexible, and single-step regrowth process with good planarization for realizing buried QCLs leading to monomode, high power, and high WPE.
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| 6. |
- Metaferia, Wondwosen, et al.
(författare)
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Polycrystalline indium phosphide on silicon by indium assisted growth in hydride vapor phase epitaxy
- 2014
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 116:3, s. 033519-
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Tidskriftsartikel (refereegranskat)abstract
- Polycrystalline InP was grown on Si(001) and Si(111) substrates by using indium (In) metal as a starting material in hydride vapor phase epitaxy (HVPE) reactor. In metal was deposited on silicon substrates by thermal evaporation technique. The deposited In resulted in islands of different size and was found to be polycrystalline in nature. Different growth experiments of growing InP were performed, and the growth mechanism was investigated. Atomic force microscopy and scanning electron microscopy for morphological investigation, Scanning Auger microscopy for surface and compositional analyses, powder X-ray diffraction for crystallinity, and micro photoluminescence for optical quality assessment were conducted. It is shown that the growth starts first by phosphidisation of the In islands to InP followed by subsequent selective deposition of InP in HVPE regardless of the Si substrate orientation. Polycrystalline InP of large grain size is achieved and the growth rate as high as 21 mu m/h is obtained on both substrates. Sulfur doping of the polycrystalline InP was investigated by growing alternating layers of sulfur doped and unintentionally doped InP for equal interval of time. These layers could be delineated by stain etching showing that enough amount of sulfur can be incorporated. Grains of large lateral dimension up to 3 mu m polycrystalline InP on Si with good morphological and optical quality is obtained. The process is generic and it can also be applied for the growth of other polycrystalline III-V semiconductor layers on low cost and flexible substrates for solar cell applications.
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| 7. |
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| 8. |
- Metaferia, Wondwosen, et al.
(författare)
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Selective area heteroepitaxy of InP nanopyramidal frusta on Si for nanophotonics
- 2013
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Ingår i: Indium Phosphide and Related Materials (IPRM), 2012 International Conference on. - : IEEE. - 9781467317252 ; , s. 81-84
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Konferensbidrag (refereegranskat)abstract
- InP nanopyramidal frusta on InP and InP precoated Si substrates were grown selectively from nano-imprinted circular openings in silicon dioxide mask using a low pressure hydride vapor phase epitaxy reactor. The grown InP nanopyramidal frusta, octagonal in shape, were characterized by Atomic Force Microscopy, Scanning Electron Microscopy and Photoluminescence. The growth is extremely selective and uniform over the entire patterned area on both substrates. The measured diagonal of the top surface is 30 nm and 90 nm for the nanopyramidal frusta grown from 120 nm and 300 nm diameter openings, respectively. The size and morphology as well as the optical quality of these pyramidal frusta make them suitable templates for quantum dot structures for nano photonics and silicon photonics.
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| 9. |
- Parillaud, O., et al.
(författare)
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Multi-regrowth steps for the realization of buried single ridge and μ-stripes quantum cascade lasers
- 2013
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Ingår i: 2013 International Conference on Indium Phosphide and Related Materials (IPRM). - : IEEE. - 9781467361309 ; , s. 6562597-
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Konferensbidrag (refereegranskat)abstract
- We report on the realization of buried single ridge and μ-stripes quantum cascade lasers using HVPE and MOVPE regrowth steps of semi-insulating InP:Fe and Si doped layers. We present here the preliminary results obtained on these devices. The reduction of the thermal resistance achieved using semi-insulating InP:Fe for regrowth planarization and μ-stripe arrays approaches are shown and performance perspectives are addressed.
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| 10. |
- Sun, Yanting, et al.
(författare)
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Direct Heterojunction of Polycrystalline InP/Si by Hydride Vapor Phase Epitaxy for Photovoltaic Application
- 2013
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Konferensbidrag (refereegranskat)abstract
- The direct heterojunction of polycrystalline InP on (001) and (111) silicon substrates was realized by indium assisted heteroepitaxy in a hydride vapor phase epitaxy system. The poly-InP growth under various temperatures and dopant incorporation were investigated. A coherent InP/Si interface and poly-InP growth rate > 20 μm/hour was observed by cross-sectional scanning electron microscopy (SEM). Effective n-type sulfur doping was revealed by stain-etching. The material properties of poly-InP were characterized by powder X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), photoluminescence (PL), and Raman spectroscopy. A preferential crystalline orientation of (111) plane with substrate orientation dependent grain size was observed. Raman spectroscopy characterization at different locations on poly-InP surface reveals residual tensile strain in InP on silicon. High optical quality of poly-InP is revealed by PL measurement.
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