SUBLIMATION GROWTH OF HIGH-PURITY ZNSE SINGLE-CRYSTALS AND PHOTOLUMINESCENCE

High-purity zinc selenide single crystals have been grown by sublimation method with a Zn reservoir, starting from commercial grade high-purity elements, zinc and selenium. The photoluminescence (PL) spectra at 4.2 K of the as-grown crystals consist of a free excitonic line and the I-1(d) line with its three phonon replica without satelite peaks indicative of impurities. After the Zn-dip treatment of the sample, an intense free excitonic line and the I2 line were observed instead of the disappearing I1d line. Purification effect achieved through the repetition of sublimation growth was confirmed when using less pure starting source materials.