Determination of the impact of Bi content on the valence band energy of GaAsBi using x-ray photoelectron spectroscopy
We investigate the change of the valence band energy of GaAs1-xBix (0<0.025) as a function of dilute bismuth (Bi) concentration, x, using x-ray photoelectron spectroscopy (XPS). The change in the valence band energy per addition of 1 % Bi is determined for strained and unstrained thin films using a linear approximation applicable to the dilute regime. Spectroscopic ellipsometry (SE) was used as a complementary technique to determine the change in GaAsBi bandgap resulting from Bi addition. Analysis of SE and XPS data together supports the conclusion that ∼75% of the reduction in the bandgap is in the valence band for a compressively strained, dilute GaAsBi thin film at room temperature.
Collar, K; Li, J; Jiao, W; Guan, Y; Losurdo, M; Humlicek, J; Brown, AS
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