Document Type

Article

Date of Original Version

2022

Department

Physics

Abstract

Wide band-gap semiconducting oxides have strong expectations in providing the high mobility while retaining their properties at heterojunction interfaces that is critical for microelectronic device applications. Recently, measurements in bulk BaSnO3 (BSO) perovskite demonstrated significantly higher room temperature mobility with values within 100- 320 cm2/V · s range1–4. Though ionized impurity scattering is a dominant contribution that limits the mobility at high doping levels, the impact can be avoided by using effective doping techniques. That leaves the inelastic carrier phonon scattering to affect the mobility as only the polar optical (LO) phonons can mediate energy exchanges between the hot carriers and the lattice. In this case, the mobility values can be as high as 500 cm2/V · s for electron concentrations >1 x 1019cm-3. 5Knowledge of mechanisms for polar phonon interactions and phonon decay routes at different temperatures in the system where screening of ionic potential is relatively weak is essential. From the fundamental point of view, lattice vibrations (LO- and TO- phonons) and their characteristics is key in quantifying and modeling the oxide material’s complex dielectric function6,7. The phonon-damping rate (G) is more important and critical parameter than the vibration frequency (W). The damping rate relates straightforwardly to homogeneous linewidth Dn [cm-1] = G/2pc for Raman resonances that are usually studied using traditional(spontaneous) Raman scattering spectroscopy techniques. Transparent oxides have been a subject of a few theoretical and experimental studies. In particular, cubic lattice BSO has been modeled using density functional theory (DFT) to predict lattice parameters, band structure, carrier scattering rates, vibrational spectra, and dielectric function5,7–9. With regard to the experimental studies, some of the earlier optical measurements indicated a presence of strong Raman active modes2,9–11.

Publication Title

Appl. Phys. Lett.

Volume

120

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