Optoelectronic Properties in Monolayers of Hybridized Graphene and Hexagonal Boron Nitride
Optoelectronic Properties in Monolayers of Hybridized Graphene and Hexagonal Boron Nitride
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DOI：
10.1103/physrevlett.108.226805
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发表时间：
2012-06-01
影响因子：
8.6
通讯作者：
Grossman, Jeffrey C.
中科院分区：
文献类型：
--
作者：
Bernardi, Marco;Palummo, Maurizia;Grossman, Jeffrey C.
我们利用密度泛函理论、GW和Bethe-Salpeter计算解释了碳硼氮（CBN）单层的电子能隙和光吸收光谱的性质。能带结构和光吸收是由C畴尺寸而不是成分（如块状半导体合金的习惯）来调节的。C和BN准粒子态在C和BN的能量上是分开的，在带边缘附近的能量很少混合，那里的状态主要是C的特征。所得的光吸收光谱有两个明显的峰，其能量和相对强度随成分的变化而变化，与实验结果一致。单分子层在C畴内存在强束缚激子，其结合能在0.5-1.5 eV之间，这取决于C畴的大小。光电性质是由整体单层带结构产生的，不能理解为块状C和BN畴性质的叠加。
We explain the nature of the electronic energy gap and optical absorption spectrum of carbon-boron-nitride (CBN) monolayers using density functional theory, GW and Bethe-Salpeter calculations. The band structure and the optical absorption are regulated by the C domain size rather than the composition (as customary for bulk semiconductor alloys). The C and BN quasiparticle states lie at separate energy for C and BN, with little mixing for energies near the band edge where states are chiefly C in character. The resulting optical absorption spectra show two distinct peaks whose energy and relative intensity vary with composition in agreement with the experiment. The monolayers present strongly bound excitons localized within the C domains, with binding energies of the order of 0.5-1.5 eV dependent on the C domain size. The optoelectronic properties result from the overall monolayer band structure, and cannot be understood as a superposition of the properties of bulklike C and BN domains.