  Supersymmetric models with singlet extensions can accommodate single- or
multi-step first-order phase transitions (FOPT) along the various constituent
field directions. Such a framework can also produce Gravitational Waves,
detectable at the upcoming space-based interferometers, e.g., U-DECIGO. We
explore the dynamics of electroweak phase transition and the production of
Gravitational Waves in an extended set-up of the Next-to-Minimal Supersymmetric
Standard Model (NMSSM) with a Standard Model singlet right-handed neutrino
superfield. We examine the role of the new parameters compared to NMSSM on the
phase transition dynamics and observe that the occurrence of a FOPT, an
essential requirement for Electroweak Baryogenesis, typically favours a
right-handed sneutrino state below 125 GeV. Our investigation shows how the
analysis can offer complementary probes for physics beyond the Standard Model
besides the collider searches.
