Survival coefficient of Ga(5s2S1/2) sputtered from a GaAs surface

The effect of ambient oxygen gas on the survival probability for an excited Ga(5s) atoms to escape from a mono-crystalline GaAs (100) crystal without suffering tunneling de-excitation was investigated from measurements of photons emitted through the 5s2S1/2 → 4p2P3/2, 1/2 transition (417.20 nm, 403.3 nm lines) by Ar+ bombardment using optical spectroscopic technique. A Doppler analysis of the emitted line profile under an oxygen-free condition gave A/a = (5.2 ± 0.6) × 104 m/s. The transition rate for the resonant de-excitation of Ga(5s) was estimated as R ∼ 1.8 × 1013 s−1 at atom-surface distance of 2 × 10−10 m. The experimental result obtained was discussed in connection with the light-intensity dependence of the 417.2 nm spectral line on the distances from the target surface. The experimental result on the ambient oxygen gas effect was also discussed.