  We have investigated the electronic and thermoelectric properties of
half-Heusler alloys NiTZ (T = Sc, and Ti; Z = P, As, Sn, and Sb) having 18
valence electron. Calculations are performed by means of density functional
theory and Boltzmann transport equation with constant relaxation time
approximation, validated by NiTiSn. The chosen half-Heuslers are found to be an
indirect band gap semiconductor, and the lattice thermal conductivity is
comparable with the state-of-the-art thermoelectric materials. The estimated
power factor for NiScP, NiScAs, and NiScSb reveals that their thermoelectric
performance can be enhanced by appropriate doping rate. The value of ZT found
for NiScP, NiScAs, and NiScSb are 0.46, 0.35, and 0.29, respectively at 1200 K.
