Atomically thin two-dimensional layers such as molybdenum disulfide, MoS2, are promising materials for nanoelectronics due to their exceptional electronic and optical properties. An inter-atomic potential has been developed that can accurately describe the thermodynamic and structural properties of MoS2 sheets, including defects and transitions between different structural phases. A new type of “ripple” defect has been identified as a favorable host for sulfur vacancy defects. A train of moving ripplocation defects may be able to “sweep out” sulfur vacancy defects from key regions within 2D devices.