The rate of radiative recombination in the nitride semiconductors and alloys

The radiative recombination rates of free carriers and lifetimes of free ex citons have been calculated in the wide band gap semiconductors GaN, InN, a nd AlN of the hexagonal wurtzite structure, and in their solid solutions Ga xAl1-xN, InxAl1-xN and GaxIn1-xN on the base of existing data on the energy band structure and optical absorption in these materials. We determined th e interband matrix elements for the direct optical transitions between the conduction and valence bands, using the experimental photon energy dependen ce of absorption coefficient near the band edge. In our calculations we ass umed that the material parameters of the solid solutions (the interband mat rix element, carrier effective masses, and so on) could be obtained by a li near interpolation between their values in the alloy components. The temper ature dependence of the energy gap was taken in the form proposed by Varshn i [Physica 34, 149 (1967)]. The calculations of the radiative recombination rates were performed in a wide range of temperature and alloy compositions . (C) 1999 American Institute of Physics. [S0021-8979(99)06917-0].