Photocrystallization of Cold Condensed Amorphous TlCl Films Detected by UV Absorption Measurements

Photocrystallization was found in the cold condensed amorphous TlCl films by UV absorption measurements under irradiation at 77 K with UV light of less than 80 µW·cm-2 intensity for 8 h. The photocrystallized films are of a microcrystalline nature characterized by the absence of the 1st exciton peak, but crystal growth occurs by annealing at room temperature and the sharp 1st exciton peak appears.