Time resolved Magneto-Photoluminescence in $InAs_{x}P_{1-x}$ alloys*

Recently, g-factor engineering has attracted much attention for potential applications in spintronics. In the case of $InAs_{x}P_{1-x}$ alloys, a wide range of g-factors, including g=0, can be achieved. In order to probe the band-structure and the dynamics of photo-excited carriers in $InAs_{x}P_{1-x}$ epitaxial films with x=0.13, 0.4, we measured NIR absorption spectra at 4K and 300K, as well as magneto- photoluminescence spectra in both the time and frequency domain for magnetic fields in the range of 0-15T and temperatures in the range of 4-90K. From the temporal measurements, we observed strong tunability in the relaxation dynamics as a function of excitation wavelength. We present these experimental observations and compare them with theoretical calculations.