INTERMEDIATE RANGE BETWEEN N-DOPED GAP AND GAP1-XNX ALLOYS - DIFFERENCE IN OPTICAL-PROPERTIES

Metalorganic vapor phase epitaxy (MOVPE) grown GaP1-xNx metastable all oys with relatively dilute nitrogen concentrations (0.03% less than or equal to 1.4%, i.e., 1 x 10(19) less than or equal to [N] less than o r equal to 3 x 10(20) cm(-3)) have been studied with photoluminescence (PL). These nitrogen concentrations are especially interesting becaus e they mediate between the N-doped GaP ([N] similar to 10(19) cm(-3)), where the PL spectrum is represented by the emissions due to excitons bound to nitrogen atom pairs (NNi, i = 1, 2, 3,...), and the alloy, w here the PL should be associated with the band gap. The nitrogen conce ntration dependence of the PL spectra shows that the dominant emission changes from the shallow NNi centers (NN4, NN5) to the deepest one (N N1) with increasing x. The temperature dependence of the PL shows a si milar systematic change in the spectrum. the integrated PL intensity v ersus x relationship indicates that at x > 0.4% (approximate to 1 x 10 (20) cm(-3)) nitrogen-doped GaP may be properly looked upon as a GaP1- xNx alloy.