The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 17 4 2019 11 26 Effect of impurities on the optical properties of KTP single crystals grown from flux Effect of impurities on the optical properties of KTP single crystals grown from flux 630 630 1301 10.29252/ijpr.17.4.630 FA Hamideh Zaliani M J Tafreshi Dariush Souri Journal Article 2019 11 26 In the present work, KTP crystals have been grown by spontaneous nucleation technique in flux medium using K6P < sub>4O13 flux. 0.4-1 °C/h cooling rates were applied in the spontaneous nucleation process. The presence and amount of impurities has been determined by using XRF. The optical transmission spectra of impure KTP crystals in the UV–visible region are discussed. The transmission cut-off is clearly shown at the optical absorption edge, as well as the rapidly reduced absorption with increasing wavelength. It is shown that the presence of impurity shifts the absorption edge of KTP towards lower energy region. The wavelength dependence of absorption coefficient is determined in the UV–visible range, and the characteristics of the optical absorption edge are discussed. Results reveal that the absorption edge and the type of optical charge carrier transition can be attributed to indirect transition for these crystals. It is shown that presence of impurity decreases the indirect band gap (Eg) of KTP crystals, causing the indirect transition absorption edge to move towards lower energy. In the present work, KTP crystals have been grown by spontaneous nucleation technique in flux medium using K6P < sub>4O13 flux. 0.4-1 °C/h cooling rates were applied in the spontaneous nucleation process. The presence and amount of impurities has been determined by using XRF. The optical transmission spectra of impure KTP crystals in the UV–visible region are discussed. The transmission cut-off is clearly shown at the optical absorption edge, as well as the rapidly reduced absorption with increasing wavelength. It is shown that the presence of impurity shifts the absorption edge of KTP towards lower energy region. The wavelength dependence of absorption coefficient is determined in the UV–visible range, and the characteristics of the optical absorption edge are discussed. Results reveal that the absorption edge and the type of optical charge carrier transition can be attributed to indirect transition for these crystals. It is shown that presence of impurity decreases the indirect band gap (Eg) of KTP crystals, causing the indirect transition absorption edge to move towards lower energy. https://ijpr.iut.ac.ir/article_1301_2df45244f09369e16ea3f9117ca45157.pdf