A transistor includes a first channel layer over a second channel layer, where the first and the second channel layers include a monocrystalline transition metal dichalcogenide (TMD). The transistor structure further includes a source structure coupled to a first end of the first and second channel layers, a drain structure coupled to a second end of the first and second channel layers, a gate structure between the source material and the drain material, and between the first channel layer and the second channel layer. The transistor further includes a spacer laterally between the gate structure and the and the source structure and between the gate structure and the drain structure. A liner is between the spacer and the gate structure. The liner is in contact with the first channel layer and the second channel layer and extends between the gate structure and the respective source structure and the drain structure.