Back-doping experiments with intentional donors (Al, Cl, Ga and In) and acceptor (Na) species have been conducted in the recrystallization travelling-heater-method (THM)-grown ZnSe single crystals. Sharp bound-exciton lines and associated two-electron or two-hole transitions appear clearly and their bind-ing energies can be accurately estimated using central cell corrections. Uni-axial stress measurements on the l1
d line at 2.783 eV and on the l2
In line at 2.7968eV confirm that the spatial symmetry of the localized centers which bind excitons is Td. Utilizing the present THM ZnSe crystal as a substrate for ZnSe layer with good optical-quality was homoepitxially grown by metalorganic-chemical- vapor-deposition and exhibited a strong donor-bound exciton line locating at 2.7964 eV, probably Al. Low-resistive n-type layer with 0.1ω·cm was achieved by doping with Al from trimethylaluminum source.