Si/β-FeSi2/Si (SFS) structures with β-FeSi2 particles on Si(001), and SFS structures with β-FeSi2 continuous films were epitaxially grown on both Si(001) and Si(111) substrates by molecular-beam epitaxy (MBE). All the samples exhibited the same photoluminescence (PL) peak wavelength of approximately 1.54 μm at low temperatures. However, the PL decay times for the 1.54 μm emission were different, showing that the luminescence originated from different sources. The decay curves of the SFS structures with β-FeSi2 continuous films were fitted assuming a two-component model, with a short decay time (~10 ns) and a long decay time (~100 ns), regardless of substrate surface orientation. The short decay time was comparable to that obtained in the SFS structure with β-FeSi2 particles. The short decay time was due to carrier recombination in β-FeSi2, whereas the long decay time was probably due to a defect-related D1 line in Si. We obtained 1.6 μm electroluminescence (EL) at a low current density of 2 A/cm2 up to around room temperature. The temperature dependence of the EL peak energy of the SFS diodes with β-FeSi2 particles can be fitted well by the semi-empirical Varshni's law. However, EL peak positions of the SFS diodes with the β-FeSi2 films showed anomalous temperature dependence; they shifted to a higher energy with increasing temperature, and then decreased. These results indicate that the EL emission originated from several transitions.
It is reported that arsenic (As) act as a surfactant in growth of cubic GaN by GSMBE, and that it improves quality of cubic of the grown layer. In this paper, we report that it is true for Halide Vapor Phase Epitaxy (HVPE) of GaN, however, it deteriorates photoluminescence intensity of the grown layer very much. It was found that in order to get optically high quality cubic GaN, it is important to prevent incorporation of As. The As autodoping in HVPE was suppressed by growing GaN layer on back side of the substrate, too. The photoluminescence intensity was improved by more than one order to magnitude by preventing the As autodoping. In HVPE, we can grow thick and pure GaN layers, though it is said that when the grown thickness exceeds 1.5 micrometers , more than 10 percent hexagonal phase is introduced for gas source molecular beam epitaxy and metalorganic vapor phase epitaxy growth of cubic GaN. Best value of the cubic component for HVPE was 2 micrometers with the cubic component of more than 99 percent.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.