The edit can be undone. Please check the comparison below to verify that this is what you want to do, and then publish the changes below to finish undoing the edit.
Latest revision | Your text | ||
Line 18: | Line 18: | ||
The In<sub>x</sub>Ga<sub>1-x</sub>N films were characterized via spectroscopic ellipsometry using the lab's [[QAS Ellipsometer|J.A. Woollam Co. vertical-variable angle spectroscopic ellipsometer]] (V-VASE) with a photon range of 0.8 eV to 4.5 eV. | The In<sub>x</sub>Ga<sub>1-x</sub>N films were characterized via spectroscopic ellipsometry using the lab's [[QAS Ellipsometer|J.A. Woollam Co. vertical-variable angle spectroscopic ellipsometer]] (V-VASE) with a photon range of 0.8 eV to 4.5 eV. | ||
In order to extract useful information about the thin films using ellipsometry, a Kramers-Kronig consistent parametric model was developed to fit the raw ellipsometric through a regression-based data analysis. In building the parametric model, each unique layer of material in the sample must be represented: Si wafer, SiO<sub>2</sub> substrate (grown on the Si wafer), In<sub>x</sub>Ga<sub>1-x</sub>N layer and a surface roughness layer (treated as a Bruggeman Effective Medium Approximation consisting of a 50/50 mixture of In<sub>x</sub>Ga<sub>1-x</sub>N film and void space. In order to represent the unique absorbing In<sub>x</sub>Ga<sub>1-x</sub>N layer, parametric dispersion relationships were used. A Cauchy layer with Urbach absorption was first used over the non-absorbing (transparent) regions of the ellipsometric data output | |||
In order to extract useful information about the thin films using ellipsometry, a Kramers-Kronig consistent parametric model was developed to fit the raw ellipsometric through a regression-based data analysis. In building the parametric model, each unique layer of material in the sample must be represented: Si wafer, SiO<sub>2</sub> substrate (grown on the Si wafer), In<sub>x</sub>Ga<sub>1-x</sub>N layer and a surface roughness layer (treated as a Bruggeman Effective Medium Approximation consisting of a 50/50 mixture of In<sub>x</sub>Ga<sub>1-x</sub>N film and void space. In order to represent the unique absorbing In<sub>x</sub>Ga<sub>1-x</sub>N layer, parametric dispersion relationships were used. A Cauchy layer with Urbach absorption was first used over the non-absorbing (transparent) regions of the ellipsometric data output before being converted to a real physical relationship using Gaussian oscillators. | |||
Top-down and cross-sectional SEM images were taken using a [[Field emission scanning electron microscope lab protocol at Queen's University|field-emission scanning electron microscope (SEM)]] in the Queen's Physics Department. | Top-down and cross-sectional SEM images were taken using a [[Field emission scanning electron microscope lab protocol at Queen's University|field-emission scanning electron microscope (SEM)]] in the Queen's Physics Department. |