| 1. |
- Berrier, Audrey, et al.
(författare)
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Carrier transport through a dry-etched InP-based two-dimensional photonic crystal
- 2007
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 101:12, s. 123101-1-123101-6
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Tidskriftsartikel (refereegranskat)abstract
- The electrical conduction across a two-dimensional photonic crystal (PhC) fabricated by Ar/Cl-2 chemically assisted ion beam etching in n-doped InP is influenced by the surface potential of the hole sidewalls, modified by dry etching. Carrier transport across photonic crystal fields with different lattice parameters is investigated. For a given lattice period the PhC resistivity increases with the air fill factor and for a given air fill factor it increases as the lattice period is reduced. The measured current-voltage characteristics show clear ohmic behavior at lower voltages followed by current saturation at higher voltages. This behavior is confirmed by finite element ISE TCAD (TM) simulations. The observed current saturation is attributed to electric-field-induced saturation of the electron drift velocity. From the measured and simulated conductance for the different PhC fields we show that it is possible to determine the sidewall depletion region width and hence the surface potential. We find that at the hole sidewalls the etching induces a Fermi level pinning at about 0.12 eV below the conduction band edge, a value much lower than the bare InP surface potential. The results indicate that for n-InP the volume available for conduction in the etched PhCs approaches the geometrically defined volume as the doping is increased.
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| 2. |
- Berrier, Audrey, et al.
(författare)
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Electrical conduction through a 2D InP-based photonic crystal - art. no. 63220J
- 2006
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Ingår i: Tuning the Optic Response of Photonic Bandgap Structures III. - : SPIE. - 9780819464019 ; , s. J3220-J3220
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Konferensbidrag (refereegranskat)abstract
- This work investigates the current transport across two-dimensional PhCs dry etched into InP-based low-index-contrast vertical structures using Ar/Cl-2 chemically assisted ion beam etching. The electrical conduction through the PhC field is influenced by the surface potential at the hole sidewalls, which is modified by dry etching. The measured current-voltage (I-V) characteristics are linear before but show a current saturation at higher voltages. This behaviour is confirmed by simulations performed by ISE-TCAD software. We investigate the dependence of the conductance of the PhC area as a function of the geometry of the photonic crystal as well as the material parameters. By comparing the experimental and simulated conductance of the PhC, we deduce that the Fermi level is pinned at 0.1 eV below the conduction band edge. The method presented here can be used for evaluating etching processes and surface passivation methods. It is also applicable for other material systems and sheds new light on current driven PhC tuning.
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| 3. |
- Anand, Srinivasan, et al.
(författare)
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High aspect ratio etching and characterization of 2D-photonic crystals in InP/InGaAsP/InP heterostructures
- 2004
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Ingår i: Photonics. - : SPIE - International Society for Optical Engineering. - 0819451703 ; , s. 78-89
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Konferensbidrag (refereegranskat)abstract
- We report on the fabrication and characterization of 2D photonic crystals (PhCs) in InP/InGaAsP/InP heterostructures. It is demonstrated that Ar/C12 based chemically assisted ion beam etching (CAIBE) is a very promising method to obtain high aspect ratio etching of PhCs in the InP-based materials. With this process, it is possible to obtain PC-holes as deep as 3 microns even for feature (PhC-hole) sizes as small as 200-250 nm. The optical characteristics of the fabricated PhC-based elements/devices such as line-defect waveguides, in-plane resonant cavities and drop-filter based on contra-directional coupling will be reported. The devices were measured using end-fire coupling and the obtained results were simulated using the 2D finite difference time domain (FDTD) method including an effective loss-approximation. The etched PhC-waveguides show low transmission losses, less than 1 dB/100 mum. A quality factor of 400 for a 6 micron long cavity with 6-hole mirrors is obtained. Finally, drop-functionality in a PhC-based filter using contra-directional coupling is demonstrated.
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| 4. |
- Anand, Srinivasan, et al.
(författare)
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Towards realization of high quality 2D-photonic crystals in InP/GaInAsP/InP
- 2004
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Ingår i: 2004 International Conference on Indium Phosphide and Related Materials, Conference Proceedings. - 0780385950 ; , s. 311-313
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Konferensbidrag (refereegranskat)abstract
- Two-dimensional photonic crystals (PhCs) were etched into InP/GaInAsP/InP planar waveguides using chlorine based chemical assisted ion beam etching (CAIBE). Etching mechanisms and process parameters crucial for high quality PhC definition are discussed, with special attention to the lag-effect. The processed PhCs were optically characterized by measuring transmission through simple slabs and one-dimensional cavities. The optical properties inside the photonic bandgap are much better compared to both previously reported CAME results and results obtained with other etching methods. In particular, we measured a record quality factor of 310 for one-dimensional cavities fabricated in this material system.
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| 5. |
- Aubin, G., et al.
(författare)
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Highly dispersive photonic crystal-based guiding structures
- 2006
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Ingår i: CLEO/QELS 2006. - : Optical Society of America. - 1557528136 - 9781557528131 ; , s. 972-974
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Konferensbidrag (refereegranskat)abstract
- Propagating modes supported by Photonic-Crystal guiding structures can demonstrate very high group velocity dispersion close to a cut-off. We investigate here the wavelength dependence of the dispersion for different Photonic Crystal structures.
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| 6. |
- Benisty, H., et al.
(författare)
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Low-loss photonic-crystal and monolithic InP integration : Bands, bends, lasers, filters
- 2004
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Ingår i: Photonic Crystal Materials and Devices II. - : SPIE - International Society for Optical Engineering. - 0819452688 ; , s. 119-128
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Konferensbidrag (refereegranskat)abstract
- Practical realizations of 2D (planar) photonics crystal (PhC) are either on a membrane or etched through a conventional heterostructure. While fascinating objects can emerge from the first approach, only the latter approach lends itself to a progressive integration of more compact PhC's towards monolithic PICs based on InP. We describe in this talk the various aspects from technology to functions and devices, as emerged from the European collaboration "PCIC". The main technology tour de force is deep-etching with aspect ratio of about 10 and vertical sidewall, achieved by three techniques (CAIBE, ICP-RIE, ECR-RIE). The basic functions explored are bends, splitters/combiners, mirrors, tapers, and the devices are filters and lasers. At the end of the talk, I will emphasize some positive aspects of "broad" multimode PhC waveguides, in view of compact add-drop filtering action, notably.
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| 7. |
- Benyattou, T., et al.
(författare)
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Optical Bloch waves studied by near optical field microscopy
- 2005
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Ingår i: Journal of the Korean Physical Society. - 0374-4884 .- 1976-8524. ; 47, s. S72-S75
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Tidskriftsartikel (refereegranskat)abstract
- Photonic bandgap structures are very promising for the integration of optical function at the nanoscale level and particularly 2D structures perforated on a slab waveguide. In this context, photonic crystal waveguides obtained by removing rows of holes in the periodic structure are very interesting. We will present here, results of near field optical microscopy conducted on PCW. With a Fourier transform analysis of the image, we can image the Bloch waves propagating in the waveguide. The results are compared to FDTD simulations and we will show that the images obtained correspond to the electric field. Such result allows us to study the interaction of the optical tip with the electromagnetic field. 2D FDTD simulations of 1D photonic crystal interaction with a SNOM tip is presented. The results obtained confirm that the SNOM signal is mainly related to the electric field.
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| 8. |
- Berrier, Audrey, et al.
(författare)
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Characterization of the feature-size dependence in Ar/Cl2 chemically assisted ion beam etching of InP-based photonic crystal devices
- 2007
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Ingår i: Journal of Vacuum Science & Technology B. - : American Vacuum Society. - 1071-1023 .- 1520-8567. ; 25:1, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- The authors address feature-size dependence in Ar/Cl-2, chemically assisted ion beam etching (CAIBE) in the context of the fabrication of photonic crystal (PhC) structures. They systematically investigate the influence of various parameters such as hole diameter (115-600 nm), etch duration (10-60 min), and ion beam energy (300-600 eV) on PhC etching in InP with Ar/Cl-2, CAIBE. For a 60 min etching at an Ar-ion energy of 400 eV, the authors report an etch depth of 5 mu m for hole diameters d larger than 300 nm; the etch depth is in excess of 3 mu m for d larger than 200 nm. The evolution of roughness at the bottom of the etched holes and its dependence on hole size and etching conditions,is discussed. The physical mechanism of the observed feature-size dependent etching (FSDE) is then discussed and the effect of the process parameters is qualitatively understood using a model combining the effect of ion sputtering and surface chemical reactions. Finally, the effect of FSDE on the PhC optical properties is assessed by measuring the quality factor of one-dimensional Fabry-Perot PhC cavities. The measured quality factors show a clear trend with the etch depth: the cavity Q increases as the etch depth increases.
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| 9. |
- Berrier, Audrey, et al.
(författare)
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Feature size effects in Ar/Cl-2 chemically assisted ion beam etching of InP-based protonic crystals
- 2006
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Ingår i: 2006 International Conference on Indium Phosphide and Related Materials Conference Proceedings. - NEW YORK : IEEE. - 9780780395572 ; , s. 341-344
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Konferensbidrag (refereegranskat)abstract
- This work addresses feature size effects (the lag-effect and roughness development) in chemically assisted ion beam etching (CAIBE) etching of InP-based photonic crystals. Photonic crystal fields The slope of the etch,with varying hole size and periods were etched with different etching times. depth versus diameter cures (lag-curves) reveals an aspect ratio dependence, with an etch limiting aspect ratio of the order of 25. A model of the etch rate specific to Ar/Cl-2 CAIBE is proposed. We calculate the etch rate using a physico-chemical model which takes in to account the effect of Ar-ion sputtering and surface chemical reactions. lit addition, it combines the aspect ratio dependence of the gas conductance of the etched holes. Finally, the bottom roughness of the etched holes is examined; its origin and evolution are discussed.
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| 10. |
- Berrier, Audrey, et al.
(författare)
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Feature size effects in chemically assisted ion beam etching of InP-based photonic crystals - art. no. 632707
- 2006
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Ingår i: Nanoengineering: Fabrication, Properties, Optics, and Devices III. - BELLINGHAM, WA : SPIE-INT SOC OPTICAL ENGINEERING. - 0819464066 ; , s. 32707-32707
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Konferensbidrag (refereegranskat)abstract
- This work addresses feature size effects (the lag-effect and roughness development) in chemically assisted ion beam etching (CAIBE) etching of InP-based photonic crystals. Photonic crystal fields with varying hole size and periods were etched with different etching times. The slope of the etch depth versus diameter curves (lag-curves) reveals a hole size dependence, with a critical aspect ratio higher than 25. A model for the etch rate specific to Ar/Cl-2 CAIBE is proposed. We calculate the etch rate using a physico-chemical model which takes in to account the effect of Ar-ion sputtering and surface chemical reactions. In addition, it combines the aspect ratio dependence of the gas conductance of the etched holes. The origin and evolution of the bottom roughness of the etched holes is examined. The impact of the feature size dependence of the etching on the photonic crystal optical properties is then assessed by measuring the quality-factor of one-dimensional Fabry-Perot cavities using the Internal Light Source method, and discussed in terms of hole shape and depth. A systematic trend between the determined quality factor (Q) and the lag-effect is evidenced: Q decreases from about 250 to 60 when the hole depth drops from 5 mu m to 2 mu m.
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