27 research outputs found
What Common Elementary Practices Impact Teacher Efficacy?
Efficacy and its impact on student outcomes have often been researched. Specific practices within an elementary setting that impact teacher efficacy has not been widely researched. This research focused on gathering the perceptions of elementary teachers regarding which experiences had impacted their feelings of efficacy positively or negatively. This qualitative research followed a grounded theory process. Data collection methods involved gathering data from an email survey and following up with a focus group which allowed triangulation of data and findings. Participants from a midwestern suburban high-performing elementary school were selected for this research based on the assumption that high-performing schools would likely have teachers who self-identified as having higher efficacy. I wanted higher efficacy educators because as an outcome I wanted to create a list of practices for administrators that could build efficacy for staff, sustain efficacy if it was in place, and avoid harming successful efficacy cycles or practices for new or newer administrators when joining a building. Findings suggested that administrators should pay particular attention to four general areas to support or sustain efficacy. The four areas for positive impact include any practices that impact an educator\u27s time, areas that include support for the teacher, relationships, and reflective practices. Within these themes there were very specific practices that could be put into place for immediate impacts on efficacy, for example, one of the practices that received a 90.9% positive impact on efficacy was receiving a public oral or written compliment from a peer or administrator. The findings also suggested some practices that hinder or have a negative impact on efficacy. The two themes that emerged negatively were professional development based on how it is launched and handled and curriculum matters also dependent on how the decisions surrounding the curriculum are handled. Areas for future research include a longitudinal study that follows teachers from teacher development through their teaching career as well as research that would look at the cultural components of efficacy as that has not been covered in the existing literature
Are Characteristics Of A Professional Learning Community Guiding Student Achievement
The research question addressed in this capstone was, are characteristics of a PLC guiding student achievement? The inspiration for this capstone was sparked by an unexplainable anomaly within a school district\u27s MCA performance data between schools within their district and an intense interest in a DuFour’s research addressing professional learning communities. The author of this case-study style research looked to examine if characteristics of a PLC can be present and guide student performance without a fully functioning and formal PLC school-wide structure. This study documents that singular aspects of a PLC can guide student achievement and likens a co-taught classroom structure to a small and efficient PLC structure. This capstone also addresses the history of education reform and the common missteps of trying to initially implement a PLC structure
L’inclusion financière des néo-alphabètes en Côte d’Ivoire : une plus-value de l’alphabétisation fonctionnelle
L’inclusion financière constitue un enjeu majeur du développement économique de la Côte d’Ivoire. Toutefois, le faible taux de bancarisation des individus âgés de 15 ans et plus, estimé à 19,7% en 2016, et le taux de pénétration de la microfinance qui est de l’ordre de 10% selon l’APIF-CI (2019, p.10) demeurent des obstacles importants dans la réalisation de l’inclusion financière. C’est pourquoi, pour faciliter l’accès des usagers aux services financiers, des efforts sont déployés par l’Etat et ses partenaires en vue d’améliorer les offres et services financiers (notamment les paiements, transferts de fonds et épargnes). Dans un pays comme la Côte d’Ivoire où 56,1% des personnes âgées de 15 ans et plus sont analphabètes, l’inclusion financière devient nécessaire dans la conception et la gestion des projets et programmes d’alphabétisation fonctionnelle. L’inclusion financière constitue une plus-value de l’alphabétisation fonctionnelle dans la mesure où elle contribue à l’accélération des process d’utilisation des services financiers et de la finance numérique. L’inclusion financière participe à la lutte contre la pauvreté et au développement économique
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Defect Mediated Sub-Bandgap Optical Absorption in Ion-Implanted Silicon Nano-Wire Waveguide Photodetectors
Silicon has numerous benefits as a photonic integrated circuit platform, including optical transparency from 1.1 µm to greater than 5 µm, tight optical confinement due to its high index of refraction, high third order non-linearity, and lack of two photon absorption at wavelengths above 2.2 µm. Additionally, silicon photonics has the added benefit of decades of fabrication knowledge from the CMOS industry. Despite these advantages, an enormous challenge exists in two areas, optical sources for silicon photonic integrated circuits, and on the other end, optical detectors for silicon photonic integrated circuits. The same bandgap energy that leads to the optical transparency at telecom and mid-infrared wavelengths, limits both generation and detection in this same regime. This dissertation focuses on the detection problem, exploring the use of defect-mediated sub-bandgap optical absorption in ion-implanted silicon nano-wire waveguides.
Section I of this dissertation focuses on fabrication and the ion-implantation process, including a primer on Shockley-Read-Hall theory and its application to defect-mediated sub-bandgap optical absorption.
Section II examines the devices for use at telecom wavelengths. In Chapter 4, the fabrication and characterization of metal-semiconductor-metal ion-implanted silicon nano-wire waveguide photodiodes is examined. These devices require minimal fabrication, are compatible with standard CMOS fabrication processes, and exhibited responsivities as high as 0.51 A/W and frequency responses greater than 2.6 GHz. With improved fabrication tolerances, frequency responses of greater than 10 GHz are expected. Chapter 5 examined these ion-implanted photodiodes in a p-i-n configuration as a high speed data interconnect, demonstrating error free operation at 10 Gbs with expected sensitivities approaching that of Ge detectors.
Section III extends the above research to longer wavelengths, starting with data reception at 1.9 µm in Chapter 6, exhibiting an approximate 5 dB penalty in sensitivity compared to the same diodes at 1.55 µm, at a data rate of 1 Gbs, limited by RC due to the 2 mm length of the device. Chapter 7 goes even further, characterizing Si+ implanted silicon nano-wire waveguides for operation between 2.2 µm and 2.35 µm. These devices showed responsivities as high as 9.9 mA/W, with internal quantum efficiencies approaching 5%. Chapter 8 concludes with the characterization of Zn+ implanted silicon nano-wire waveguides operating in the same wavelength regime, exhibiting higher overall responsivity, albeit at a much higher reverse bias. These long wavelength devices open up new areas of research for silicon photonics, allowing for CMOS compatible detectors operating into the mid-infrared region, useful for chemical sensing, free-space communications, and medical imaging
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Metal-semiconductor-metal ion-implanted Si waveguide photodetectors for C-band operation
Metal-semiconductor-metal Si waveguide photodetectors are demonstrated with responsivities of greater than 0.5 A/W at a wavelength of 1550 nm for a device length of 1mm. Sub-bandgap absorption in the Si waveguide is achieved by creating divacancy lattice defects via Si+ ion implantation. The modal absorption coefficient of the ion-implanted Si waveguide is measured to be ≈185 dB/cm, resulting in a detector responsivity of ≈0.51 A/W at a 50V bias. The frequency response of a typical 1mm-length detector is measured to be 2.6 GHz, with simulations showing that a frequency response of 9.8 GHz is achievable with an optimized contact configuration and bias voltage of 15V. Due to the ease with which these devices can be fabricated, and their potential for high performance, these detectors are suitable for various applications in Si-based photonic integrated circuits
Measuring M2 values for on-wafer vertical cavity surface emitting lasers
We report on M2 measurements taken for on-wafer vertical cavity surface emitting lasers (VCSELs). We measured M2 for oxide-confined VCSELs and photonic crystal (PhC) VCSELs of similar lasing aperture sizes
Characterization of Single-Mode Vertical Cavity Surface-Emitting Lasers
A high-quality single-mode beam is desirable for the efficient use of lasers as light sources for optical data communications and interconnects, however there is little data which characterizes operating ranges and near-field beam qualities of Vertical Cavity Surface Emitting Lasers (VCSELs), which has resulted in a lack of analysis of these devices. Measures of beam quality include beam-quality factor (M2 ), Side-Mode-Suppression-Ratio (SMSR) and RMS linewidth. M2 is a measurement of how closely the beam is to an ideal Gaussian. SMSR is the difference, in dB, between the amplitude of the primary peak and the amplitude of the next highest peak of the output spectrum, with single-mode operation defined by a SMSR \u3e 30 dB. RMS linewidth is a second moment calculation involving the power spectral density, where smaller RMS linewidth indicates higher beam quality. Utilizing a novel vertical M2 setup in which on-wafer VCSEL M2 can be measured, a study was conducted on the relation between M2 , SMSR and RMS linewidth, for various oxide-confined VCSELs of varying aperture sizes and Photonic Crystal (PhC) VCSELs of varying aperture sizes and photonic crystal configurations. First, the operating range of the VCSEL was determined utilizing a Semiconductor Parameter Analyzer to obtain the LIV characteristics. Along with this measurement, spectral data was collected using an Optical Spectrum Analyzer at several key operating points, which allowed the RMS linewidths and SMSRs of the devices to be calculated at these points. The novel beam-profiler setup was used to measure the device’s M2 . Initial results show a strong correlation between the measures of beam quality, with increasing SMSR, corresponding to M2 values closer to 1, and single-mode operation characterized by a M2 of less than 1.5. A strong correlation between RMS linewidth and M2 was also seen, with increasing RMS linewidths corresponding to an increase in M2
Ar+-Implanted Si-Waveguide Photodiodes for Mid-Infrared Detection
Complementary metal-oxide-semiconductor (CMOS)-compatible Ar+-implanted Si-waveguide p-i-n photodetectors operating in the mid-infrared (2.2 to 2.3 µm wavelengths) are demonstrated at room temperature. Responsivities exceeding 21 mA/W are measured at a 5 V reverse bias with an estimated internal quantum efficiency of 3.1%–3.7%. The dark current is found to vary from a few nanoamps down to less than 11 pA after post-implantation annealing at 350 °C. Linearity is demonstrated over four orders of magnitude, confirming a single-photon absorption process. The devices demonstrate a higher thermal processing budget than similar Si+-implanted devices and achieve higher responsivity after annealing up to 350 °C
Characterization of Single-Mode Vertical Cavity Surface-Emitting Lasers
A high-quality single-mode beam is desirable for the efficient use of lasers as light sources for optical data communications and interconnects, however there is little data which characterizes operating ranges and near-field beam qualities of Vertical Cavity Surface Emitting Lasers (VCSELs), which has resulted in a lack of analysis of these devices. Measures of beam quality include beam-quality factor (M2 ), Side-Mode-Suppression-Ratio (SMSR) and RMS linewidth. M2 is a measurement of how closely the beam is to an ideal Gaussian. SMSR is the difference, in dB, between the amplitude of the primary peak and the amplitude of the next highest peak of the output spectrum, with single-mode operation defined by a SMSR \u3e 30 dB. RMS linewidth is a second moment calculation involving the power spectral density, where smaller RMS linewidth indicates higher beam quality. Utilizing a novel vertical M2 setup in which on-wafer VCSEL M2 can be measured, a study was conducted on the relation between M2 , SMSR and RMS linewidth, for various oxide-confined VCSELs of varying aperture sizes and Photonic Crystal (PhC) VCSELs of varying aperture sizes and photonic crystal configurations. First, the operating range of the VCSEL was determined utilizing a Semiconductor Parameter Analyzer to obtain the LIV characteristics. Along with this measurement, spectral data was collected using an Optical Spectrum Analyzer at several key operating points, which allowed the RMS linewidths and SMSRs of the devices to be calculated at these points. The novel beam-profiler setup was used to measure the device’s M2 . Initial results show a strong correlation between the measures of beam quality, with increasing SMSR, corresponding to M2 values closer to 1, and single-mode operation characterized by a M2 of less than 1.5. A strong correlation between RMS linewidth and M2 was also seen, with increasing RMS linewidths corresponding to an increase in M2