Ambipolar MoS<inline-formula><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="TIMEQ1"><mml:msub><mml:mrow/><mml:mi> </mml:mi></mml:msub><mml:mstyle mathvariant="bold"><mml:mn>2</mml:mn></mml:mstyle></mml:math></inline-formula> enabled through high-<inline-formula><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="TIMEQ2"><mml:mrow><mml:mi> </mml:mi><mml:mi>ε</mml:mi></mml:mrow></mml:math></inline-formula> ferroelectric P(VDF-TrFE)

The p-type and n-type transistors are the basic components for building CMOS electronic devices for logic circuits. Most two-dimensional materials are n-type due to strong electron doping by intrinsic structural defects. Notably, the p-type conductivity of MoS$_{2}$ is hardly achievable by the limited electric field modulation from the low dielectric constant of Si/SiO$_{2}$. However, through strong dielectric screening of a high dielectric constant substrate and powerful polarization electric field of ferroelectric material, the p-type transition of MoS$_{2}$ can be realized. In this paper, with the help of ferroelectric field modulation of high dielectric constant P(VDF-TrFE), a significant modulation of the band structure of MoS$_{2}$ is realized, and finally, a flexible p-type modulation of MoS$_{2}$ is obtained. The band changes and electrical properties of MoS$_{2}$ on three different dielectric constant substrates, including Si/SiO$_{2}$, hBN, and P(VDF-TrFE), were quantitatively studied with Kelvin probe force microscopy (KPFM). Fermi level changes and band n-p transitions of MoS$_{2}$ under ferroelectric modulation were also systematically investigated by KPFM. The ferroelectric modulation of the MoS$_{2}$ Fermi level can realize a wide range of flexible modulation up to nearly 900 meV. This work reveals the device physics of the realization of p-type transport from the band perspective and provides an effective and viable reference for p-type modulation of other two-dimensional materials. It also provides a boost for the application of MoS$_{2}$ in high-performance electronic and optoelectronic devices.