GROWTH AND OPTICAL-PROPERTIES OF HO DOPED N-TYPE INDIUM SELENIDE

n-InSe and Ho doped n-InSe (n-InSe:Ho) single crystals were grown by a method which is similar to the direct freezing method. The crystals u sed in this study were grown in our crystal growth laboratory. The ing ots had no cracks and voids on the surface. There was no process to po lish and clean the samples because of the natural mirror-like cleavage faces. The X-ray Laue back-reflection method was used to test the cry stallinity of the prepared sample. The absorption measurements were ca rried out in n-InSe:Ho sample in the temperature range from 10 to 320 K. The exciton energies for n = 1 were calculated as 1.315. 1.302, 1.2 66 and 1.238 eV in n-InSe:Ho at 10, 100, 200 and 280 K, respectively. The exciton energies for n = 2 in n-InSe:Ho are 1.328, 1.322, 1.318 at 10, 60 and 80 K, respectively. The exciton binding energy of n-InSe:H o was calculated as 17.3 meV. The direct band gaps for n-InSe:Ho are 1 .332, 1.313, 1.283 and 1.255 eV at 10, 100, 200, 280 K, respectively.