With the strategies detailed above in place, one may expect to finally lift the current RC limitation of two-terminal TMDC photodetectors. Ultimately, and under the assumption that drift as well as diffusion times remain insignificant, the speed limit of such optimized devices will be determined by their intrinsic material response times. Assessing and optimizing these is therefore relevant in determining materials and architectures that provide the highest prospects for true GHz performance in optical applications. For example, 2PC measurements of an MoS2 monolayer in a two-terminal photodetector with a simple metal-semiconductor-metal configuration without external bias has revealed an intrinsic response with a fast component of 3-5 ps and a slow component of 80-100 ps. This picosecond response is derived from defect-related recombination processes. Upon photoexcitation, the thermalization and cooling of excited carriers occurs on the time scale of 0.5-1 ps. After that, these charge carriers are captured by different defects such as surface defects and grain boundaries with different lifetimes, which determine the intrinsic speed limit of the photodetector.