LPE InP layers grown in the presence of rare-earth elements

Preparation and characterisation of InP layers grown by Liquid Phase Epitaxy with the addition of several rare-earth (RE) elements into the growth melt is reported and the influence of Ho, Er, Nd Pr, and Yb is compared. Low-temperature photoluminescence (PL) spectra have been measured for various levels of excitation power and temperature. The major manifestation of the RE admixture is the pronounced narrowing of PL curves and the corresponding appearence of fine spectral features. Particularly in the case of Nd and Pr admixtures the acceptor related PL band exhibits a structure that permits an individual determination of acceptor and donor binding energies. Temperature dependent Hall effect and capacitance–voltage curves also show quite dramatic impact of Pr and Nd on shallow impurity and free-carrier concentrations: they were reduced by as much as three orders of magnitude.