Time resolved spectroscopy of n-type InAsP films*

In this study, we employed ultrafast Time Resolved Differential Reflectivity (TRDR) and ultrafast time resolved Magneto-optic Kerr Effect (MOKE) on InAs_xP_1-x ternary alloy. In recent years, InAs_xP_1-x ternary alloys have attracted extensive attention due to the immense prospect for various optoelectronic applications including optical telecommunication, broadband photodetectors, mid-IR lasers, and also quantum communication devices. ^1,2 As the switching rates in devices are pushed to higher frequencies in optoelectronic and spintronic devices, it is required to perform comprehensive studies of the carrier and spin relaxation dynamics in semiconductors on a femto-second timescale. Here we report carrier and spin dynamics of n-type InAs_xP_1-x films in a broad optical region (700 nm and 1000 nm). Also, we observed the generation of coherent oscillations which could be related to photo-induced coherent acoustic phonons. The InAs_xP_1-x films are ~1.2 micron thick grown on semi-insulating InP (001) wafers and the carrier concentrations are estimated to be 1x10¹⁷ cm^--3.
1- Journal of Applied Physics 115, 193503 (2014).
2- Applied Physics Letters 102 (22), 222102 (2013).