Gravitational wave has become a new window to explore our universe. Among many events detected so far, GW170817 was the first binary neutron star gravitational wave event joint with electromagnetic observations, which revolutionized our understanding of neutron star physics and the origin of kilonova. However, due to a limited detector sensitivity at the high frequency around kHz, we did not observe the most energetic part of this event---the catastrophic merger of the two neutron stars. In this talk, I will present the latest developments in the design study of kHz detectors for observing the merger signals, which include the upgrade plans for existing facilities and designs of the next-generation gravitational-wave observatory.