Photoluminescence from bulk HfS2 grown by the chemical vapor transport method is reported. A series of emission lines is apparent at low temperature in the energy range of 1.4 - 1.5 eV. Two groups of the observed excitonic transitions followed by their replicas involving acoustic and optical phonons are distinguished using classical intensity correlation analysis. The emission is attributed to the recombination of excitons bound to iodine (I2) molecules intercalated between layers of HfS2. The I2 molecules are introduced to the crystal during the growth as halogen transport agents in the growth process. Their presence in the crystal is confirmed by secondary ion mass spectroscopy.
@article{arxiv.2209.08520,
title = {Excitonic luminescence of iodine-intercalated HfS$_2$},
author = {N. Zawadzka and T. Woźniak and M. Strawski and I. Antoniazzi and M. Grzeszczyk and K. Olkowska-Pucko and Z. Muhammad and J. Ibanez and W. Zhao and J. Jadczak and R. Stępniewski and A. Babiński and M. R. Molas},
journal= {arXiv preprint arXiv:2209.08520},
year = {2023}
}