Orientation-dependent pseudomorphic growth of InAs for use in lattice-mismatched mid-infrared photonic structures

In this study, InAs was deposited on GaAs (100) and GaAs (111)B 2 degrees towardssubstrates for the purpose of differentiating the InAs growth mode stemming from strain and then analyzed using in-situ reflection high energy electron diffraction, scanning electron microscopy, Raman spectroscopy, reflectance spectroscopy, and atomic force microscopy. The procession of InAs deposition throughout a range of deposition conditions results in assorted forms of strain relief revealing that, despite lattice mismatch for InAs on GaAs (approximately 7%), InAs does not necessarily result in typical quantum dot/wire formation on (111) surfaces, but instead proceeds two-dimensionally due primarily to the surface orientation

New Colonialism in Developmental Aid

Conventional wisdom suggests United States’ economic foreign aid is wasted and should be cut. In challenging this conventional wisdom, I argue that though there is potential for good through foreign aid, bilateral aid programs like that of the Forum on China-Africa Cooperation resemble neo-colonialism. This paper examines international aid’s effects on establishing debt traps, promoting exploitation, and reinforcing hierarchy. Through analysis of primary and secondary evidence, including but not limited to UNCTAD and WWF-SIGHT reports, I look at how the effects of international aid contribute to the sovereignty of the recipient countries. My findings reveal that though Chinese international aid and investment has creates several positive short-term changes in African economies, these advances come with a cost. Due to a lack of regulations on aid-based development projects, powerful countries are allowed to take advantage of both the recipients’ natural resources and political sovereignty

Expeditionary Learning: Mi vida en perspectiva

This work outlines and supports the use of Expeditionary Learning to help 8th grade Spanish 1 students to understand mental and emotional health. Outlined is a single In-depth Investigation plan (IDI) that walks through the activities, experts, and service the students will be participating in, in order to learn about mental and emotional health

The Relationship Between Perceived Overqualification and Job Attitudes and Behaviors: The Moderating Role of Psychological Empowerment

It has been shown that employees who perceive to be overqualified in their roles are more likely to display negative attitudes and behaviors; however, little attention has been paid to the possible moderators of this relationship. Therefore, the present study proposed that psychological empowerment would moderate the relationship between perceived overqualification and job attitudes (affective commitment and careerist attitudes) and behaviors (counterproductive work behaviors). It was hypothesized that the relationship between perceived overqualification and these job attitudes and behaviors would be weaker for employees with higher levels of psychological empowerment than for employees with lower levels of psychological empowerment. Results from a self-report survey of 138 employed individuals showed that psychological empowerment moderated only the relationship between perceived overqualification and counterproductive behaviors. Results also showed that perceived overqualification was negatively related to affective commitment and careerist attitudes, regardless of levels of psychological empowerment. Consistent with past findings, these results suggest that the negative consequence of overqualification on counterproductive behaviors is avoidable and emphasize the importance of person-job fit in hiring employees in order to reduce the negative outcomes of perceived overqualification

THE MENTOR IN YOU:EXPECTED AND RECIEVED STUDY ABROAD PREPARATION

When you think of studying abroad, visions of exotic locations and wild adventures come to mind. However, have you ever thought about the process before going abroad? This study examines the steps and programs offered to a student before going abroad. The research process involved examining existing literature about the study abroad process and what programs are offered at Illinois State University. Two interviews were conducted with students who have already studied abroad and one interview with a student who is about to study abroad. Further investigation included reviewing blogs and examining the data through narrative analysis. The research findings concluded that the mentor needs mentorship and the study abroad program repeats the same information from past events

Spectroscopy studies of straincompensated mid-infrared QCL active regions on misoriented substrates

In this work, we perform spectroscopic studies of AlGaAs/InGaAs quantum cascade laser structures that demonstrate frequency mixing using strain-compensated active regions. Using a three-quantum well design based on diagonal transitions, we incorporate strain in the active region using single and double well configurations on various surface planes (100) and (111). We observe the influence of piezoelectric properties in molecular beam epitaxy grown structures, where the addition of indium in the GaAs matrix increases the band bending in between injector regions and demonstrates a strong dependence on process conditions that include sample preparation, deposition rates, mole fraction, and enhanced surface diffusion lengths. We produced mid-infrared structures under identical deposition conditions that differentiate the role of indium(strain) in intracavity frequency mixing and show evidence that this design can potentially be implemented using other material systems

Plasmon Waveguide Resonance Raman Spectroscopy

Raman spectra were collected from a 1.25 M aqueous pyridine solution, 100-nm polystyrene film or a trimethyl(phenyl)silane monolayer at a plasmon waveguide interface under total internal reflection (TIR). The plasmon waveguide resonance (PWR) interface consisted of a sapphire prism/49 to 50 nm Au/548 to 630 nm SiO2 and a monolayer, thin film or aqueous analyte. The Raman peak area as a function of incident angle was measured using a 785-nm excitation wavelength, and was compared to the Raman peak area obtained at a sapphire or sapphire/50 nm Au interface. In contrast to measurements at a bare sapphire prism, increased surface sensitivity and signal were obtained from the PWR interface. In contrast to measurements at a bare Au film where only p-polarized incident light generates an enhanced interfacial electric field, plasmon waveguide interfaces enable excitation with orthogonal polarizations using s- or p-polarized incident light. The Raman scatter from a monolayer was recorded at the PWR interface with a signal-to-noise ratio of 5.6 when averaging 3 accumulations with 3 min acquisition times using nonresonant excitation, whereas no signal was recorded from a monolayer at the sapphire interface. The reflected light from the interface enabled the identification of the incident angle where the maximum Raman scatter was produced, and the Raman signal generated at the plasmon waveguide interface was modeled by the enhanced interfacial mean square electric field relative to the incident field. In comparison to the techniques on which this work was based (i.e., PWR spectroscopy, TIR Raman spectroscopy at the prism interface, and surface plasmon resonance (SPR) Raman spectroscopy at the prism/Au interface), chemical specificity was added to PWR spectroscopy, a signal enhancement mechanism was introduced for TIR Raman spectroscopy, and polarization control of the interfacial electric field was added to SPR Raman spectroscopy

Near IR Scanning Angle Total Internal Reflection Raman Spectroscopy at Smooth Gold Films

Total internal reflection (TIR) Raman and reflectivity spectra were collected for nonresonant analytes as a function of incident angle at sapphire or sapphire/smooth 50 nm gold interfaces using 785 nm excitation. For both interfaces, the Raman signal as a function of incident angle is well-modeled by the calculated interfacial mean square electric field (MSEF) relative to the incident field times the thickness of the layer being probed in the Raman measurement (DRS). The Raman scatter was reproducibly enhanced at the interface containing a gold film relative to the sapphire interface by a factor of 4.3−4.6 for aqueous pyridine or 2.2−3.7 for neat nitrobenzene, depending on the analyzed vibrational mode. The mechanism for the increased Raman signal is the enhanced MSEF at incident angles where propagating surface plasmons are excited in the metal film. The background from the TIR prism was reduced by 89−95% with the addition of the gold film, and the percent relative uncertainty in peak area was reduced from 15 to 1.7% for the 1347 cm−1 mode of nitrobenzene. Single monolayers of benzenethiol (S/N = 6.8) and 4-mercaptopyridine (S/N = 16.5) on gold films were measured by TIR Raman spectroscopy with 785 nm excitation (210 mW) without resonant enhancement in 1 min

Pseudomorphic growth of InAs on misoriented GaAs for extending quantum cascade laser wavelength

The authors have studied the impact of epilayer strain on the deposition of InAs/GaAs on (100) and (111)B with 2 degrees offset toward 2-1-1 surfaces. Consequences of a 7% lattice mismatch between these orientations in the form of three-dimensional growth are less apparent for (111)B with 2 degrees offset toward 2-1-1 surfaces compared to (100). By exploring a range of molecular beam epitaxy process parameters for InAs/GaAs growth and utilizing scanning electron microscopy, atomic force microscopy, and Raman spectroscopy to evaluate the quality of these strained layers, the authors develop empirical models that describe the influence of the process conditions in regards to surface roughness with \u3e92% accuracy. The smoothest InAs/GaAs samples demonstrated average surface roughness of 0.08 nm for 10 um-squre areas, albeit at very low deposition rates. The authors have found the most important process conditions to be substrate temperature and deposition rate, leading us to believe that controlling diffusion length may be the key to reducing defects in severely strained structures. InGaAs/AlGaAs quantum cascade laser structures were also produced on (111)B with 2 degrees offset toward 2-1-1 to take advantage of the piezoelectric effect, and the modified laser transitions due to these effects were observed

Are U.S. Congregations Patching the Social Safety Net? Trends from 1998 to 2012

As social services become increasingly privatized amid a federal policy environment that provides a means-tested, temporary social safety net, there is potential for a larger contribution by congregations as social service providers. Using data from a nationally representative sample of religious congregations collected in 1998, 2006, and 2012, we examine whether congregations have increased service activity over time, and whether provision varies by the congregation’s community-level context. We find that post-Great Recession, congregations are more likely to engage in broad social services and in “core” services that address basic economic needs. Congregations in high-poverty neighborhoods were less likely to provide services in 1998 than congregations in low-poverty neighborhoods; after the recession, not only are significantly more congregations in high-poverty neighborhoods providing services than in 1998, they have closed the gap with congregations in low-poverty neighborhoods and are equally likely to be providing any services regardless of neighborhood poverty. Our findings highlight the importance of service measurement to determine the prevalence of congregation-level service provision and suggest that congregational service provision may be a substantial yet inadequate substitute for the public safety net