The emerging family of atomically thin materials is fueling the development of conceptually new technologies [1] in highly efficient optoelectronics [2,3] and photonic applications, [4] to name a few. The large variety of bandgap values found in layered transition-metal dichalcogenides (TMDCs) [5,6] make these materials especially suited for transistor applications. TMDCs are compounds with the general formula MX 2 , where M is a transition metal, e.g., Mo and W, and X is an element of the chalcogen group, S, Se, and Te. They appear in a layered structure where the metal forms a hexagonal plane and the chalcogenides are positioned over and under this plane in either a trigonal prismatic (2H), as shown in Figure 1a, or octahedral (1T) stacking configuration. [7] In the semiconducting 2H systems, the compounds show a transition from indirect bandgap in bulk materials to direct bandgap in single layers. [8] Transient currents in atomically thin MoTe 2 field-effect transistors (FETs) are measured during cycles of pulses through the gate electrode. The curves of the transient currents are analyzed in light of a newly proposed model for charge-trapping dynamics that renders a time-dependent change in the threshold voltage as the dominant effect on the channel hysteretic behavior over emission currents from the charge traps. The proposed model is expected to be instrumental in understanding the fundamental physics that governs the performance of atomically thin FETs and is applicable to the entire class of atomically thin-based devices. Hence, the model is vital to the intelligent design of fast and highly efficient optoelectronic devices.Single-and few-layered TMDCs have been implemented in a wide range of applications, ranging from thin film transistors, [9] digital electronics and optoelectronics, [2,10,11] flexible electronics, [12] and up to energy conversion and storage devices. [13] However, the defect states in TMDCs have an ambivalent nature and can have a major positive or negative impact on the performance of atomically thin devices. The presence of defects in photodetectors can be beneficial since it has been shown to immobilize charges at the channel which improves the gain in photodetectors [14] and produces nonvolatile memory mechanisms. [15] On the other hand, large hysteresis caused, for example, by charge traps [2] and significant Schottky barriers [16] at the metal-semiconductor interface are still a major design challenge for the realization of novel device architectures. They have been shown to cause degradation in the performance of transistors [17] and generate high levels of flicker noise. [18,19] To overcome these challenges, hysteresis is usually avoided by encapsulation [20,21] or operation under high vacuum. [22,23] Most of the current research into surface states of TMDCs has focused on the chemical origins of charge trapping. A full understanding of their effect on the electrical properties is still lacking, hindering the optimization of functional components. While hysteresis has been sho...