The phonon modes of materials contain critical information on the quality of the crystals. Phonon modes also offer a wide range of polarization-dependent resonances in infrared that can be tailored to applications that require large dielectric function contrast in different crystal directions. Here, we investigate the far-field characteristics of MOCVD-grown Ga2O3 thin films. With a combination of cross-polarization FTIR and AFM characterization techniques, we propose an easy and non-invasive route to distinguish kappa and beta phases of Ga2O3 and study the quality of these crystals. Using numerical methods and cross-polarization spectroscopy, the depolarization characteristics of beta-Ga2O3 are examined and depolarization strength values as high as 0.495 and 0.76 are measured, respectively, for 400 and 800 nm-thick beta-Ga2O3. The strong birefringence near optical phonon modes of an 800 nm beta-Ga2O3 on a sapphire substrate is used to obtain several polarization states for the reflected light in the second atmospheric window 8-14 mu m. We anticipate that our findings open a new path for material characterization and wave plate design for the mid-IR range and offer novel possibilities for the future of IR on-chip photonics, thanks to the compatibility of beta-Ga2O3 with standard nanofabrication technology.

MOCVD-grown Ga2O3 thin films for polarization-sensitive infrared photonics / Dereshgi, Sina Abedini; Lee, Junhee; Ceneda, Daniele; Larciprete, Maria Cristina; Centini, Marco; Razeghi, Manijeh; Aydin, Koray. - In: APL MATERIALS. - ISSN 2166-532X. - 12:1(2024), p. 011125. [10.1063/5.0177705]

MOCVD-grown Ga2O3 thin films for polarization-sensitive infrared photonics

Ceneda, Daniele
Membro del Collaboration Group
;
Larciprete, Maria Cristina
Membro del Collaboration Group
;
Centini, Marco
Membro del Collaboration Group
;
Aydin, Koray
Supervision
2024

Abstract

The phonon modes of materials contain critical information on the quality of the crystals. Phonon modes also offer a wide range of polarization-dependent resonances in infrared that can be tailored to applications that require large dielectric function contrast in different crystal directions. Here, we investigate the far-field characteristics of MOCVD-grown Ga2O3 thin films. With a combination of cross-polarization FTIR and AFM characterization techniques, we propose an easy and non-invasive route to distinguish kappa and beta phases of Ga2O3 and study the quality of these crystals. Using numerical methods and cross-polarization spectroscopy, the depolarization characteristics of beta-Ga2O3 are examined and depolarization strength values as high as 0.495 and 0.76 are measured, respectively, for 400 and 800 nm-thick beta-Ga2O3. The strong birefringence near optical phonon modes of an 800 nm beta-Ga2O3 on a sapphire substrate is used to obtain several polarization states for the reflected light in the second atmospheric window 8-14 mu m. We anticipate that our findings open a new path for material characterization and wave plate design for the mid-IR range and offer novel possibilities for the future of IR on-chip photonics, thanks to the compatibility of beta-Ga2O3 with standard nanofabrication technology.
2024
Depolarization; Fourier transform infrared spectroscopy; Numerical methods; Phonons; Sapphire
01 Pubblicazione su rivista::01a Articolo in rivista
MOCVD-grown Ga2O3 thin films for polarization-sensitive infrared photonics / Dereshgi, Sina Abedini; Lee, Junhee; Ceneda, Daniele; Larciprete, Maria Cristina; Centini, Marco; Razeghi, Manijeh; Aydin, Koray. - In: APL MATERIALS. - ISSN 2166-532X. - 12:1(2024), p. 011125. [10.1063/5.0177705]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1704614
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