Band anticrossing in diluted AlxGa1-xAs1-yNy (x <= 0.37,y <= 0.04)

We show that the conduction band structure of dilute AlxGa1-xAs1-yNy with x <= 0.37 and y 0.04 can be described consistently by the experimentally motivated band anticrossing model. The interband transition energies E-, E-+ Delta(ind 0), and E+ have been derived from a full line shape fit to photomodulated reflectance (PR) spectra recorded at room temperature. The PR data were taken (a) from a series of Al0.06Ga0.94As1-yNy samples with y <= 0.04 and (b) from a set of AlxGa1-xAs0.99N0.01 layers with x <=0.37. The latter series covers the range of Al concentrations where the AlxGa1-xAs band gap energy EM is expected to cross the nitrogen-induced energy level EN. The resulting nitrogen- and Al-concentration dependent interband transition energies are described by the band anticrossing model using a matrix element for the coupling between the nitrogen-induced states and the extend lowest conduction band states of CMN=2.32 eV and a nitrogen level energy EN=(1.625+0.069x) eV, the latter measured with respect to the GaAs valence band edge.