Figures

Figure 1

Photoluminescence spectra of the Ga1-xAlxN layers recorded at room temperature

Figure 2

Energy of the experimental PL features versus the aluminium molar ratio x. The full circles correspond to near band edge lunminescence and diamonds to other PL features. The alloy band edge from Ref. [5] is plotted in dotted line.

Figure 3

Raman spectra of the Ga1-xAlxN layers recorded at room temperature in the configuration. Insert : Raman spectra of the Ga0.28Al0.72N layer recorded in the same configuration at three temperatures.

Figure 4

Resonance profile of the A1(LO) phonon versus detuning (Eg - EL)/hLO (see text). The dotted line is only a guide for the eye.

Figure 5

Plot of the calculated frequencies (solid line) and of the frequencies measured ultraviolet excitation (open circles), for the A1(LO) phonon. For comparison, the dotted line gives the variation of the frequencies measured under visible excitation.

© 1998 The Materials Research Society