Spontaneous and stimulated photoluminescence on nitrogen A-line and NN-pair line transitions in GaAs1−x Px : N

Abstract

In accord with recent absorption measurements, photoluminescence measurements on crystals grown from a Ga solution, as well as on some vapor epitaxial crystals, indicate that the A line in GaAs_1−x P_x : N is higher in energy than formerly believed. Also, the NN‐pair emission peak (E_NN) has been determined more accurately relative to the A‐line peak (E_N), and relative to E_Γ and E_x. For crystal composition x less than 0.9, only a single NN‐pair emission band is observed with E_NN = E_Γ at x ≈ 0.30. The A‐line is broad (⩾ 50 Å) with E_N = E_Γ at x ≈ 0.40. For E_N ≈ E_Γ or E_NN ≈ E_Γ the recombination probability on transitions involving N traps may be resonantly enhanced. If E_Γ is close to or degenerate with E_N or E_NN, carrier reemission from N traps to the conduction band is fast, and stimulated emission involving N or NN trap centers can lead to line narrowing because the excess electron population can readjust rapidly between trap centers and the Γ conduction band.