Absorption spectra of heavily Cu+-doped KCl, SrCl2 and KI crystals

Abstract

Optical absorption and magnetic circular dichroism spectra have been investigated in heavily Cu⁺‐doped KCl, SrCl₂, and KI crystals (the concentration is more than 0.1 mole%). In KCl, CuCl microcrystal is formed in the annealed crystals and gives rise to two sharp bands in the 350–380 nm region, which are attributable to the Z_1,2 and Z₃ exciton bands in the microcrystal by analogy with the Z_1,2 and Z₃ exciton bands of pure CuCl crystal. The two bands of the microcrystal shift toward lower energy and approach to the pure CuCl exciton band spectrum with increasing microcrystal size. Similar microcrystal has been suggested to be formed in CuCl‐doped SrCl₂, and CuI microcrystal in CuI‐doped KI.