© 2022 Author(s).We propose three vertical heterostructures of two-dimensional materials composed of MoS 2 and AlN single layers to emulate biological synaptic behaviors. We aim to show a so-called healthy synaptic behavior with an N vacancy-defected heterostructure, dysfunctional synaptic behavior with a pristine heterostructure, and repaired synaptic behaviors using an N intercalated heterostructure. We compare the abilities of those proposed artificial synapses using density functional theory, Boltzmann transport methods, and real-time time dependent density functional theory. We find that the vacancy-defected heterostructure can mimic the biological synaptic behaviors better than the others. We conclude a relation between learning abilities and synaptic abilities. A combination of logic and memory abilities is positively correlated with synaptic abilities. These results are significant to emulate the brain on a large scale, with ultrathin and low power consumption heterostructures.