i am wondering how to set parameters? more E-dos and K in PLODS option?
Yes, you should definitely increase the number of energy points, e.g., to something like 401 instead of 101 for [-2,2] eV interval, and increase the k-point sampling in the direction (A or B depending on which one is set to be parallel to the MoS2 plane) perpendicular to the transport C-direction, e.g., try 12 k-points for MoS2 - it should be larger than what was used for the corresponding SCF device calculation.
I note that it is a matter of convergence, so the number given above might need adjustment. Also, there will always be some noise (which depends on the actual device studied) and exponential tails going to the gap regions, since DOS calculation assumes some broadening.