Monte Carlo simulations of disorder in ZnSnN2 and the effects on the electronic structure

Electrically Benign Defect Behavior in Zinc Tin Nitride Revealed from First Principles

“…The DLCN model shown in Fig. 1 belongs to space group Pna2 1 and consists of a 32-atom unit cell, consistent with that reported elsewhere [2]. Note that there are infinite possible configurations for the DLCN models when different cell sizes are considered; however, within the 128-atom supercell, we found only one configuration owing to the strong geometrical constraint of the local charge neutrality.…”

“…However, a certain level of disorder in the cation sublattice appears to be unavoidable because of the very low cation order-disorder transition temperature [2]. At low temperature, the disordered phase strictly retains the local charge neutrality, in which each N atom is necessarily coordinated by two Sn and two Zn atoms.…”

“…We refer to such a structure as the disordered structure with local charge neutrality (DLCN). It is reported that the electronic structure of the DLCN is almost identical to that of the ordered structure [2,15]. Thus, the DLCN should be ideal as a photoabsorber, unless its defects are detrimental to its efficiency.…”

“…They report that Sn-on-Zn antisite (Sn Zn ) and O-on-N (O N ) substitutional defects have low formation energies with deep donor levels and thus do not cause the BM shift in ZnSnN 2 . However, given recent experimental and theoretical findings [1,2,9,10,[14][15][16], this conclusion needs to be reviewed. This motivated us to reevaluate point defects in ZnSnN 2 including currently unexplored hydrogen impurities.…”

“…We thus consider both ordered and DLCN models in our defect calculations. Note that cation disorder breaks local charge neutrality at very high temperature (>1750 K [2]). Some authors use special quasirandom structures (SQS) to examine the behavior of the cation disordered phase [9,10].…”