Temperature Dependence of Time-resolved Photoluminescence in Mercuric Iodide

Abstract

Time-resolved photoluminescence (TRPL) of red mercuric iodide single crystal was measured from 10 K to 110 K. Several near band-gap exciton lines were found in 530 nm and a broad band was found at 630 nm. At near band-gap region photoluminescence comprises fast and slow decay components. Free excitons convert into bound excitons much more efficiently than the bound into the free so that non-radiative decay becomes dominant. At 10 K the dominant decay of bound excitons was radiation. With increasing temperature non-radiative decay became gradually dominant so that luminescent intensity of bound exciton line decreased and lifetime shortened quickly, especially from 20 K to 30 K. The TRPL experiment revealed that 630 nm band originates from the radiative recombination of donor-acceptor pairs. The central wavelength of the band shifted toward shorter wavelength with increasing temperature and the intensity decay can be depicted as t -n(r). The recombination rate of the donor-acceptor pairs is dependent of wavelength and temperature.

Time-resolved photoluminescence of red mercuric iodide

“…The PL of mercuric iodide was extensively studied by several groups. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Novikov and Pimonenko studied PL at low temperatures and observed three primary luminescent bands. Several sharp lines near the band gap were ascribed to the annihilation of the free and bound excitons.…”