Monolayer transition metal dichalcogenide heterojunctions, including vertical and lateral p–n junctions, have attracted considerable attention due to their potential applications in electronics and optoelectronics. Lattice-misfit strain in atomically abrupt lateral heterojunctions, such as WSe₂–MoS₂, offers a new band-engineering strategy for tailoring their electronic properties. However, this approach requires an understanding of the strain distribution and its effect on band alignment. Here, we study a WSe₂–MoS₂ lateral heterojunction using scanning tunnelling microscopy and image its moiré pattern to map the full two-dimensional strain tensor with high spatial resolution. Using scanning tunnelling spectroscopy, we measure both the strain and the band alignment of the WSe₂–MoS₂ lateral heterojunction. We find that the misfit strain induces type II to type I band alignment transformation. Scanning transmission electron microscopy reveals the dislocations at the interface that partially relieve the strain. Finally, we observe a distinctive electronic structure at the interface due to hetero-bonding.

单层过渡金属二硫化氢异质结，包括垂直和横向p–n结，由于其在电子和光电子领域的潜在应用而备受关注。原子突变的横向异质结中的晶格失配应变，例如WSe ₂ -MoS ₂，为定制其电子特性提供了一种新的能带工程策略。但是，这种方法需要了解应变分布及其对能带对准的影响。在这里，我们研究WSe ₂ –MoS ₂使用扫描隧道显微镜对横向异质结进行扫描，并对其莫尔条纹图像进行成像，以高空间分辨率绘制完整的二维应变张量。使用扫描隧道光谱法，我们测量了WSe ₂ -MoS ₂横向异质结的应变和能带对准。我们发现失配应变诱导II型到I型条带对齐转换。扫描透射电子显微镜显示在界面处的位错可部分缓解应变。最后，由于异质键合，我们在界面处观察到独特的电子结构。