Encapsulation by hexagonal boron nitride (hBN) has been widely used to address intrinsic properties of two-dimensional (2D) materials. The hBN encapsulation, however, can alter properties of 2D materials through interlayer orbital hybridization. In this paper, we present measurements of temperature dependence of photoluminescence intensity from monolayer MoS₂ encapsulated by hBN flakes. The obtained temperature dependence shows an opposite trend to that of previously observed in a monolayer MoS₂ on a SiO₂ substrate. This is caused by the existence of stable momentum-forbidden dark excitons in the hBN-encapsulated MoS₂. Ab-initio band-structure calculations have shown that orbital hybridization between MoS₂ and hBN leads to upward shift of Γ-valley of MoS₂, which results in lowering of energy of the momentum-forbidden dark excitons. This work shows an important implication that the hBN-encapsulated structures used to address intrinsic properties of two-dimensional crystals can alter basic properties of encapsulated materials.

六方氮化硼（hBN）封装已被广泛用于解决二维（2D）材料的固有特性。然而，hBN封装可通过层间轨道杂交改变2D材料的属性。在本文中，我们介绍了由hBN薄片封装的单层MoS ₂的光致发光强度对温度的依赖性。所获得的温度依赖性显示出与先前在SiO ₂衬底上的单层MoS _2中观察到的相反的趋势。这是由于在hBN封装的MoS _2中存在稳定的禁止动量的暗激子引起的。从头算带结构计算表明，MoS ₂之间的轨道杂化hBN导致MoS ₂的Γ谷向上移动，从而降低了禁止动量的暗激子的能量。这项工作表明了一个重要的含义，即用于解决二维晶体固有特性的hBN封装结构可以改变封装材料的基本特性。