Amnuyswat, Kittiphong
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Preferred name
Amnuyswat, Kittiphong
Alternative Name
Amnuyswat, K.
Main Affiliation
Email
kittiphong.am@kmitl.ac.th
2 results
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Item type:Publication, Hybrid Functional Calculation of Defects in Pseudo-binary Indium Oxynitride(2016-06-01); Indium oxynitride (InO<inf>x</inf>N<inf>y</inf>) is an attractive material that shows multi-functionality in electronic and optical applications due to its wide range tunable band gap. However there were only few studies available for this interesting material, especially on defect structure. In this work, first-principles calculation based on Density Functional Theory (DFT) within the Heys, Scuseria and Ernzerhof (HSE) hybrid functional for exchange-correlation energy was performed to investigate atomic structure, electronic properties and role of oxygen (O) defects occurred by means of their defect formation energies. The defect formation energies of both oxygen defects were compared with all possible native point defects in indium nitride. Our results revealed that O atom prefers to substitute in N site since it has lowest formation energy for all equilibrium crystal growth conditions. This result is consistent with the experimental observations by RF magnetron sputtering method. Moreover, the energy gap of indium nitride calculated by HSE method is 0.710 eV. The HSE calculation showed that the O antisite slightly widening the indium nitride band gap to 0.766 eV while the N vacancy gives wider indium nitride band gap of 1.410 eV. The complex defects of N vacancy and O antisite were also performed and discussed. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of exchange-correlation and GW approximations on electrical property of cubic, tetragonal and orthorhombic CH3NH3PbI3(2017-01-02); A first-principle calculations based on van der Waals-corrected Density Functional Theory (vdW-DFT) is performed to investigate atomic structure of methyl ammonium lead iodine (CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf>) which is a key material for high efficiency solid-state solar cell. A temperature dependent symmetry was previously reported which also included in this study. DFT calculation of electronic and optical properties are systematically studied with semi-local, non-local exchange-correlation and post-DFT approximation including PBE, HSE06 hybrid functional and GW. Relativistic effect in lead ion was taken into account by incorporating spin-orbit coupling (SOC) effect to obtain more accurate band gap of this material. With GW-SOC functional, our results of band gap calculations showed good agreement between DFT calculations and experimental studies which confirmed that this computational scheme is suitable for high accuracy material design, e.g. for solar cell applications.