Figure 2 (IMAGE)

Osaka University

Figure 2

Caption

Frequency-dependent refractive index and extinction coefficient of semi-insulating β-Ga2O3 (left) and doped β-Ga2O3 epilayer (right) along the a crystal axis (E||a) and along the b crystal axis (E||b). The gradual increase in the bulk's refractive index and extinction coefficient with increasing frequency is ascribed to phonon absorption at higher frequencies. The rapid increase in the epilayer's refractive index and extinction coefficient with decreasing frequency is due to the effect of free carriers. The Drude-Lorentz model is represented by the black dashed curves. Since β-Ga2O3 is an anisotropic crystal, its complex refractive index differs along different crystal directions. The refractive index is higher along b axis than along a axis. In the epilayer's case, the anisotropic difference between the two axes in the low-frequency region is relatively small because the refractive index is dominated by the effect of free carriers.

Credit

Osaka University

Usage Restrictions

None

License

Licensed content

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.