Tight-binding quantum chemical calculations of electronic structures of indium tin oxide

We report a theoretical study on the electronic structures of indium oxide (In₂O₃) and indium tin oxide (ITO) carried out using our original tight-binding quantum chemical calculation program "Colors", which is over 5,000 times faster than the conventional first-principles quantum chemical calculation method. The calculated band gap of In₂O ₃ is in good agreement with the experimental results, although the value obtained by conventional first-principles calculation is less than half the experimental one. The electronic structures of In₂O₃ calculated by our tight-binding method are consistent with those obtained by first-principles calculations. Furthermore, the doping of tin atoms into In ₂O₃ increased the band gap, which is also in good agreement with the experimental tendency. Hence, we confirmed that our tight-binding quantum chemical calculation method was very effective for investigation and predicting the electronic structures of In₂O ₃ and ITO crystals with high accuracy and reliability in spite of its high calculation speed.