### Abstract

We report on the experimental observation of direct interband-critical-point transitions and phonon modes in B_{x}Ga_{1−x}As alloys (0 < x < 0.03) and their evolution with increasing boron concentration using spectroscopic ellipsometry and Raman scattering. Our results are compared to the corresponding values in the GaN_{y}As_{1−y} (0 < y < 0.037) material system. For B_{x}Ga_{1−x}As, we obtain only a small bowing coefficient of the E_{g}(x) dependence in contrast to the giant redshift of the GaN_{y}As_{1−y} band-gap energy with y. The higher lying interband-transition energies of B_{x}Ga_{1−x}As (E_{1}, E_{1} + Δ_{1}, E_{0}′, E_{2}, and E_{1}′) are slightly redshifted with increasing boron concentration. A similar behavior is found for the critical points E_{0}′, E_{2}, and E_{1}′ in GaN_{y}As_{1−y}. In B_{x}Ga_{1−x}As, we observe, as in GaN_{y}As_{1−y}, a two-mode phonon behavior using Raman scattering. However, from infrared-ellipsometry or -transmission experiments, we can estimate that the oscillator strength or polarity of the BAs-like phonon is at least one order of magnitude smaller than the oscillator strength of the GaN-like phonon measured at a GaN_{y}As_{1−y} layer with comparable thickness and composition. All results will be explained using a simple model that takes into account the different nature of the chemical bonds in both alloy types.

Original language | English (US) |
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Journal | Physical Review B - Condensed Matter and Materials Physics |

Volume | 67 |

Issue number | 19 |

DOIs | |

State | Published - May 22 2003 |

### ASJC Scopus subject areas

- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics

## Fingerprint Dive into the research topics of 'Interband transitions and phonon modes in B<sub>x</sub>Ga<sub>1−x</sub>As (0 < x < 0.03) and GaN<sub>y</sub>As<sub>1−y</sub> (0 < y < 0.037): A comparison'. Together they form a unique fingerprint.

## Cite this

_{x}Ga

_{1−x}As (0 < x < 0.03) and GaN

_{y}As

_{1−y}(0 < y < 0.037): A comparison.

*Physical Review B - Condensed Matter and Materials Physics*,

*67*(19). https://doi.org/10.1103/PhysRevB.67.195205