Variation of nature of principle donors and of surface morphology of CdSe layers with increase of their thickness and condensation temperature

A mechanism of changing the principal donor nature and its effect on the cadmium selenide layer formation and recrystallization both with the thickness growth and increase a substrate temperature were investigated. Cadmium selenide layers were prepared with thermal evaporation of a source material onto a heated glass substcate (Tsub(s)=670-830 K) in a quasi-closed volume in vacuum of approximately 0.13 nPa (Tsub(e)=1080 K). Thickness d was measured by means of MII-4. Surface morphology was investigated with EhM-5 electron microscope. Energy position of principal donor levels was determined from temperature dependences of electric conductivity. Free electron mobility was calculated from the results of the Hall effect measurement. It is shown that the increase of conductivity with the growth of a layer thickness and substrate temperature is determined with the change of principal donor nature occurring due to the layer recrystallization conditioned with the defect accumulation in the crystallite structure and in the growth process