**4. Summary**

This chapter has summarized the present advances of the photodetectors based on 2D materials. With the ongoing research on 2D materials and their heterostructures, the class of 2D materials may mature to a large extent as far as electronic applications in general and optoelectronic applications, in particular, are concerned. Despite the promising results, certain gaps need to be bridged for the swift development of 2D material-based devices. First, convenient and costeffective methods for the synthesis of high-quality 2D materials should be explored and developed. Second, several new properties of 2D materials are yet to be fully explored and understood. An exhaustive effort should be focused on exploring and understanding these properties. Third, more effort should be made to formulate the application-specific heterostructures of 2D materials. The electronic and optoelectronic applications may receive a heavy push upon concurrent improvements in material growth processes and fabrication methods.

The future applications of 2D materials depend on effective integration with the present Si-based technology. Materials like silicene, germanene etc., have brought a fresh breath to 2D materials' integration with Si-based technology. Though high-performance optoelectronic applications of 2D materials have been realized, there is still a lot of room for improvement. In general, one may not be surprised if wide-spread 2D material based applications are seen in the commercial market in the near future.
