CHARACTERIZATION OF HG1-XCDXTE HETEROSTRUCTURES BY THERMOELECTRIC MEASUREMENTS

P-on-n mercury cadmium telluride (MCT) heterostructures grown by MOCVD with As and In as n- and p-type dopants, respectively, are examined b y measuring the Seebeck and Hall coefficients between 20 and 320K. The results are analyzed regarding doping and composition of the layers b y least squares fitting the experimental profiles with the calculated temperature dependencies. The electron and hole densities of the layer s are calculated taking into account Fermi-Dirac statistics, a nonpara bolic conduction band, a parabolic valence band, a discrete acceptor l evel, and fully ionized donors. For the Seebeck coefficient, the relat ion we previously showed to be valid for p-type MCT1 is used. This rel ation relies on the thermoelectric effect in a temperature gradient re sulting from the diffusion of nondegenerate carriers scattered by LO-p honons. It also fits the observed thermoelectric properties of n-type MCT in a wide temperature range. The doping and structural parameters determined from the thermoelectric measurements agreed very well with As and In profiles obtained from secondary ion mass spectroscopy measu rements and the data obtained from analyses of infrared transmission m easurements.