Minority Carrier lifetime in VPE-GaP:N, Te at Various Excitation Levels

The photoluminescence decay at room temperature in GaP:N, Te grown by vapor phase epitaxy exhibits a nonexponential behaviour. It is pronounced at excitation densities giving rise to a minority carrier density about equal to the equilibrium majority carrier density. The experimental results are in agreement with the dominating nonradiative recombination on saturable acceptor-like centres, described by a Shockley-Read-model. From fitting the calculated decay curves in the non-exponential region the centre concentration Nt = 7 × 1014 cm−3 and the capture cross-sections σpt = 7 × 10−15 cm2 and σnt = 1 × 10−18 cm2 are estimated. A nonsaturable parallel recombination channel should exist with an effective capture probability of about 5 × 106 to 1 × 107 s−1.