基于第一性原理的密度泛函理论,研究了纤锌矿(In,Al)Ga N合金的4种构型(均匀、短链、小团簇、团簇-链共存模型)的电子结构和发光微观机理。结果表明,在In Ga N合金中,短In-N-链和小In-N团簇都局域电子在价带顶(VBM)态。当小团簇与短链...基于第一性原理的密度泛函理论,研究了纤锌矿(In,Al)Ga N合金的4种构型(均匀、短链、小团簇、团簇-链共存模型)的电子结构和发光微观机理。结果表明,在In Ga N合金中,短In-N-链和小In-N团簇都局域电子在价带顶(VBM)态。当小团簇与短链共存时,前者局域电子的能力明显强于后者,是辐射复合发光中心。然而,在Al Ga N合金中,电子在VBM态的局域受短Al-N链和小Al-N团簇的影响并不显著。合金微观结构的不同会引起电子局域的改变,从而影响材料的发光性能,并对带隙和弯曲系数有重要影响。展开更多
The ammonia adsorption on the GaN (0001) surface has been investigated by using DFT/B3LYP method combined with the cluster model approach. The dissociative adsorp- tion of NH2 and H is found thermodynamically favored ...The ammonia adsorption on the GaN (0001) surface has been investigated by using DFT/B3LYP method combined with the cluster model approach. The dissociative adsorp- tion of NH2 and H is found thermodynamically favored relative to the molecular NH3 adsorption by decreasing the total energy of 0.95 eV. The adsorption geometries of the molecular and dis- sociative NH3 are given in detail, among which the molecular NH3 bonds to the surface Ga with its lone electronic pair, and the N atom of NH2 adspecies forms the four-fold coordinated N by bridging two surface Ga atoms.展开更多
文摘基于第一性原理的密度泛函理论,研究了纤锌矿(In,Al)Ga N合金的4种构型(均匀、短链、小团簇、团簇-链共存模型)的电子结构和发光微观机理。结果表明,在In Ga N合金中,短In-N-链和小In-N团簇都局域电子在价带顶(VBM)态。当小团簇与短链共存时,前者局域电子的能力明显强于后者,是辐射复合发光中心。然而,在Al Ga N合金中,电子在VBM态的局域受短Al-N链和小Al-N团簇的影响并不显著。合金微观结构的不同会引起电子局域的改变,从而影响材料的发光性能,并对带隙和弯曲系数有重要影响。
基金Supported by the National Natural Science Foundation of China (202730313)
文摘The ammonia adsorption on the GaN (0001) surface has been investigated by using DFT/B3LYP method combined with the cluster model approach. The dissociative adsorp- tion of NH2 and H is found thermodynamically favored relative to the molecular NH3 adsorption by decreasing the total energy of 0.95 eV. The adsorption geometries of the molecular and dis- sociative NH3 are given in detail, among which the molecular NH3 bonds to the surface Ga with its lone electronic pair, and the N atom of NH2 adspecies forms the four-fold coordinated N by bridging two surface Ga atoms.
