Minority carrier recombination lifetimes in n-type CdMgSe mixed crystals measured by means of the photothermal infrared radiometry. M.Pawlak 1,a , M.Maliński 2 1) Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziądzka 5/7, Toruń, Poland 2) Department of Electronics and Computer Science, Koszalin University of Technology, 2 Śniadeckich St. Koszalin 75-453, Poland a) Corresponding author: mpawlak@fizyka.umk.pl tel.: +48 56 611 32 37 Nicolaus Copernicus University ul. Grudziądzka 5/7 87-100 Toruń, Poland Abstract. Minority recombination lifetimes of n-type CdMgSe mixed crystals were estimated by using infrared photothermal radiometry (PTR) amplitude and phase frequency spectra. The results obtained by the PTR method indicate that the lifetimes of optically generated carriers in CdSe and Cd x Mg 1-x Se crystals are about 0.1 µs. The diffusion length of minority carrier in n-type CdSe single crystal was found to be 4.42 µm and it is in a good agreement with the literature value. It was found that with the increasing thermal-to-plasma component coefficient A the carrier concentration increases as expected from PTR theory. Keywords: II-VI semiconductors; CdMgSe mixed crystals; minority carrier diffusion length; minority recombination lifetime; photothermal radiometry. 1. Introduction. Photothermal methods are important for determination of different physical parameters of electronic materials. A photoacoustic method, which is one of the photothermal methods, was applied for example for: investigations of the optical absorption coefficient spectra of mixed crystals [1], investigations of the surface damage of semiconductor samples [2], determination of the quantum and energy efficiency of luminescence [3] or determination of the lifetimes of carriers in semiconductors [4]. In this paper another photothermal method – a photothermal radiometry (PTR) was applied for investigations of the lifetimes of optically generated carriers in a series of CdMgSe crystals.