Ultrafast photocurrent dynamics in exfoliated MoTe2

Layered van der Waals materials such as MoTe2 are attractive candidates for ultrafast structural control due to their weak inter-layer bonding and multiple quasi-stable structural allotropes with distinct transport responses. Here, using time-resolved photocurrent spectroscopy, we report on the ultrafast transport dynamics of Td and 1T'- MoTe2 integrated into ultrafast optoelectronic circuitry. We observe oscillations in the photocurrent response consistent with the frequency range of both inter-layer shear phonons and self-cavity plasmons. While the former is reported to mediate a light-induced transient phase transition between Td and 1T' structures, the absence of oscillations in encapsulated samples suggests the modified surface chemistry of samples in ambient conditions supports sub-wavelength confined plasmons within the material. These results highlight the importance of self-cavity effects in microstructured quantum materials.