Acousto-optical effect in the luminescence excitation spectrum of HgI2

A study of the photoluminescence excitation spectrum in a crystal of mercur y diiodide is reported. Each of the two luminescence bands peaking at 543 a nd 572-575 nm investigated was found to have its own excitation spectrum. T he excitation spectrum of the 575-nm line in the long-wavelength doublet ba nd has been observed to be sensitive to strong ultrasound vibrations and pr eliminary irradiation of the sample by 590-nm light. This line is associate d with radiative recombination of photocarriers at intrinsic point defects (vacancies or iodine and mercury interstitials) located close to dislocatio ns. The binding energy of the photosensitive center to a dislocation was es timated from the change in the excitation spectrum. (C) 1999 American Insti tute of Physics. [S1063-7834(99)01111-9].