A detailed comparison of measured and simulated optical properties of a short-period GaAs/Al_xGa_1−xAs distributed Bragg reflector

Abstract

A 6-period GaAs/Al0.9Ga0.1As distributed Bragg reflector (DBR) has been grown and its optical properties have been both measured and simulated. Incremental improvements were made to the simulation, allowing it to account for internal consistency error, incorrect layer thicknesses, and absorption due to substrate doping to improve simulation accuracy. A compositional depth profile using secondary-ion mass spectrometry (SIMS) has been taken and shows that the Al fraction averages 88.0% ± 0.3%. It is found that the amplitude of the transmission is significantly affected by absorption in the n-doped GaAs substrate, even though the energy of the transmitted light is well below the GaAs band gap. The wavelength of the features in the transmission spectrum are mostly affected by DBR layer thicknesses. On the other hand, the transmission spectrum is found to be relatively tolerant to changes to Al fraction.

The value of synchrotron radiation X‐ray techniques to explore microscale chemistry for ecology and evolution research

“…This specific query was designed to identify any articles published in any chosen year from any scientific domain (e.g., chemistry, materials science, or biochemistry) where the subject, abstract, or key words include any of the listed search terms. The NOT terms prevent the retrieval of articles with unrelated topics of similar acronyms, for example, "xAs," to represent a generic arsenic material (Wilson et al, 2020), or "XEs," symbolizing xenoestrogens (Alyea & Watson, 2009). Careful manual review of all of the results was then conducted, as this query designed to retrieve XES as "X-ray emission spectroscopy" may still retrieve XES as the less relevant "xanthophyll esterase" (Kishimoto et al, 2019).…”