Gate-tunable van der Waals heterostructure based on semimetallic WTe2 and semiconducting MoTe2

Programmable capability is highly demanded by adaptive multifunctional electronic and optoelectronic devices in various application fields, including logic circuits and data storage and sensing. The ideal platform to develop programmable devices is the van der Waals heterostructures (vdWHs) integrated by atomically thin layered two-dimensional transition metal dichalcogenides due to their broad distribution of bandgaps and highly tunable electrical and optical properties. Here, we demonstrated a gate-tunable MoTe2/WTe2 heterostructure based on semimetallic Td phase WTe2 and semiconducting 2H phase MoTe2. The developed devices concurrently exhibited a reversible and widely tunable rectification ratio ranging from similar to 10(-2) to 10(3), which is over 5 orders of magnitude. Correspondingly, we observed tunable self-excited photocurrent of the MoTe2/WTe2 vdWH, which can be switched between negative and positive values by gate bias. Moreover, the MoTe2/WTe2 vdWH showed an excellent photo-response with the maximum photoresponsivity up to 220mA W-1 under gate bias with an amplitude of 40. Such widely tunable properties enable the usage of the MoTe2/WTe2 vdWH in multifunctional devices for photovoltaic and logic applications.