Optical and electrical characterization of AlxGa1−xAs layers grown on GaAs obtained by a metallic-arsenic-based-MOCVD system
In this work we report results on the optical characterization of AlxGa1−xAs epitaxial layers. The layers were characterized using photoluminescence (PL) to 10 K and photoreflectance (PR) to 300 K. The AlxGa1−xAs layers resulted n-type with an electron concentration of 1×1017 cm−3 and a correspondin...
| Autores: | , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2007 |
| País: | México |
| Institución: | Instituto Politécnico Nacional |
| Repositorio: | Redalyc-IPN |
| OAI Identifier: | oai:redalyc.org:57036163058 |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=57036163058 |
| Access Level: | acceso abierto |
| Palabra clave: | Física, Astronomía y Matemáticas MOCVD AlxGa1−xAs photoreflectance photoluminescence Semiconductors growth |
| Sumario: | In this work we report results on the optical characterization of AlxGa1−xAs epitaxial layers. The layers were characterized using photoluminescence (PL) to 10 K and photoreflectance (PR) to 300 K. The AlxGa1−xAs layers resulted n-type with an electron concentration of 1×1017 cm−3 and a corresponding carrier mobility of about 2200 cm2 /V*s. The studies of the chemical composition by SIMS exhibit the presence of silicon, carbon and oxygen as the main residual impurities. The silicon concentration of around 1×1017 cm−3 is very close to the carrier concentration determined by the Hall-van der Pauw measurements. The 10 K photoluminescence response of the samples is strongly dependent on the growth temperature. Growth temperatures higher than 750◦C were necessary to detect a reasonable photoluminescence signal. The residual oxygen detected on the samples could be responsible for the weak photoluminescence signal. Photoreflectance spectra present two transitions mainly associated to GaAs and AlxGa1−xAs. In addition, short period oscillations near the GaAs band-gap energy are observed, and are interpreted as Franz-Keldysh oscillations associated to the hole-ionized acceptor (h-A−) pair modulations. Using the AlxGa1−xAs band-gap obtained by PR, we calculated the molar fraction of aluminum, giving x = 0.221 of molar fraction. |
|---|