Effects of deep levels and Si-doping on GaInP material properties investigated by means of optical methods

Abstract

Deep level characteristics in undoped and Si-doped Ga 0.51In 0.49P layers has been investigated using photocapacitance and photoluminescence (PL) methods. Ga 0.51In 0.49P layers were grown by metalorganic vapor-phase epitaxy in the temperature range 600–730 °C and with doping levels from 3.9 × 10 17 cm −3 to 1 × 10 19 cm −3 . A dominant deep level with an activation energy of about 0.98 eV was observered in all undoped samples. Further deep levels have been found with activation energies in the range 0.43–0.50 eV. Undoped samples grown at 650 °C exhibit the lowest trap concentration, with one remaining level at 0.89 eV only. A direct link of PL intensity to non-radiative recombination due to deep centers is demonstrated. Undoped samples exhibit the highest PL intensity at the growth temperature of lowest deep level density. Si doping suppresses the main deep level at ΔE T = 0.89 eV and results in an increase of PL intensity up to N D=2 × 10 18 cm −3 . Only deep levels in the energy range 0.41–0.50 eV were detectable. No DX-like effects due to Si doping were observed.