UV distributed Bragg reflectors build from porous silicon multilayers

Morales, Fuente; García, Gregorio Gómez-Jarabo; Luna, Adan; López, Rosalva Loreto; Rosendo, E.; Díaz, T.; Juárez, H.

doi:10.2971/jeos.2015.15016

Cited by 6 publications

(5 citation statements)

References 29 publications

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“…Other authors reported a mixture of OPS and titanium dioxide (TiO 2 ) to form transparent BRs in the VIS range where the oxidation process eliminates optical losses across the VIS range 23 . Several studies on BRs have been made in the UV range using different Si substrates and applying two oxidation processes [20][21][22] . The oxidation was used for stabilization of the refractive index; the authors did not compare between experimental and theoretical results, they only supported their results with the experimental reflection spectrum confirming a decrease of light absorption, and by keeping the same amplitude reflection level in the VIS and UV range.…”

Section: Porous Silicon Microcavities On Silicon Substrates and Quartmentioning

confidence: 99%

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Porous Si-SiO2 based UV Microcavities

Jiménez-Vivanco

García

Carrillo

et al. 2020

Sci Rep

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obtaining silicon-based photonic-structures in the ultraviolet range would expand the wavelength bandwidth of silicon technology, where it is normally forbidden. Herein, we fabricated porous silicon microcavities by electrochemical etching of alternating high and low refraction index layers; and were carefully subjected to two stages of dry oxidation at 350 °C for 30 minutes and 900 °C, with different oxidation times. in this way, we obtained oxidized porous silicon that induces a shift of a localized mode in the ultraviolet region. the presence of Si-o-Si bonds was made clear by ftiR absorbance spectra. High-quality oxidized microcavities were shown by SeM, where their mechanical stability was clearly visible. We used an effective medium model to predict the refractive index and optical properties of the microcavities. the model can use either two or three components (Si, Sio 2 , and air). the latter predicts that the microcavities are made almost completely of Sio 2 , implying less photon losses in the structure. the theoretical photonic-bandgap structure and localized photonic mode location showed that the experimental spectral peaks within the UV photonic bandgap are indeed localized modes. these results support that our oxidation process is very advantageous to obtain complex photonic structures in the UV region.

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Section: Porous Silicon Microcavities On Silicon Substrates and Quartmentioning

confidence: 99%

“…F. Morales has manufactured BRs at room temperature. To stabilize the optical parameters of BRs in the UV range dry oxidation is performed 22 . BRs based on Oxidized Porous Silicon (OPS) and TiO 2 were manufactured by Christian R. Ocier.…”

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confidence: 99%

Porous Si-SiO2 based UV Microcavities

Jiménez-Vivanco

García

Carrillo

et al. 2020

Sci Rep

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“…Optical losses in the VIS and UV range due to light absorption are found frequently in PS. This absorption loss impedes the fabrication of PS filters in the UV range, but these losses can be decreased if the PS structure is thermally oxidized in an oxygen environment [35,36]. Figure 6 (MF1) shows the theoretical (a) and experimental (b) absorbance spectrum of five microcavities.…”

Section: Optical Losses Due To Light Absorptionmentioning

confidence: 99%

“…However, many drawbacks have been found in these filters, such as high chemical instability, high photon losses due to light absorption, and scattering in the visible and UV ranges. Some solutions to these problems have been identified by carrying out dry oxidation in PS structures [32,34], and recently it has been possible to manufacture porous Si-SiO 2 filters (BRF and MF) in the UV range [34][35][36]. Our specific goal is integrating a PS MF in a photodetector to enlarge the responsivity spectrum bandwidth.…”

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Porous Si-SiO2 UV Microcavities to Modulate the Responsivity of a Broadband Photodetector

et al. 2020

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Porous Si-SiO2 UV microcavities are used to modulate a broad responsivity photodetector (GVGR-T10GD) with a detection range from 300 to 510 nm. The UV microcavity filters modified the responsivity at short wavelengths, while in the visible range the filters only attenuated the responsivity. All microcavities had a localized mode close to 360 nm in the UV-A range, and this meant that porous Si-SiO2 filters cut off the photodetection range of the photodetector from 300 to 350 nm, where microcavities showed low transmission. In the short-wavelength range, the photons were absorbed and did not contribute to the photocurrent. Therefore, the density of recombination centers was very high, and the photodetector sensitivity with a filter was lower than the photodetector without a filter. The maximum transmission measured at the localized mode (between 356 and 364 nm) was dominant in the UV-A range and enabled the flow of high energy photons. Moreover, the filters favored light transmission with a wavelength from 390 nm to 510 nm, where photons contributed to the photocurrent. Our filters made the photodetector more selective inside the specific UV range of wavelengths. This was a novel result to the best of our knowledge.

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“…This modulation is achieved by the application of different current pulses. This technique allows for us to design multilayer structures that are based on porous silicon, like distributed Bragg reflectors (DBRs) [ 1 , 2 , 3 ], rugate filters [ 3 , 4 ], and microcavities (MC) [ 5 , 6 , 7 ]. Furthermore, due to the high internal surface area of Psi, all of the devices mentioned above are good candidates for sensing biological and chemical substances [ 8 , 9 , 10 ] and gas [ 11 , 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Time-Resolved Spectroscopy of Ethanol Evaporation on Free-Standing Porous Silicon Photonic Microcavities

et al. 2018

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In this work, we have followed ethanol evaporation at two different concentrations using a fiber optic spectrometer and a screen capture application with a resolving capacity of 10 ms. The transmission spectra are measured in the visible-near-infrared range with a resolution of 0.5 nm. Porous Silicon microcavities were fabricated by electrochemistry etching of crystalline silicon. The microcavities were designed to have a localized mode at 472 nm (blue band). Ethanol infiltration produces a redshift of approximately 17 nm. After a few minutes, a phase change from liquid to vapor occurs and the localized wavelength shifts back to the blue band. This process happens in a time window of only 60 ms. Our results indicate a difference between two distinct ethanol concentrations (70% and 35%). For the lower ethanol concentration, the blue shift rate process is slower in the first 30 ms and then it equals the high ethanol concentration blue shift rate. We have repeated the same process, but in an extended mode (750 nm), and have obtained similar results. Our results show that these photonic structures and with the spectroscopic technique used here can be implemented as a sensor with sufficient sensitivity and selectivity. Finally, since the photonic structure is a membrane, it can also be used as a transducer. For instance, by placing this photonic structure on top of a fast photodetector whose photo-response lies within the same bandwidth, the optical response can be transferred to an electrical signal.

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UV distributed Bragg reflectors build from porous silicon multilayers

Cited by 6 publications

References 29 publications

Porous Si-SiO2 based UV Microcavities

Porous Si-SiO2 based UV Microcavities

Porous Si-SiO2 UV Microcavities to Modulate the Responsivity of a Broadband Photodetector

Time-Resolved Spectroscopy of Ethanol Evaporation on Free-Standing Porous Silicon Photonic Microcavities

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