Hi nibha,

Hope you are doing well these days,

His hypothesis was as radiation has dual nature in the same way matter should also have dual nature . That is when a matter moves , it must move as wave. He propagated the idea of the third kind of wave called matter wave .

Matter wave is an envelope of many waves of different wavelengths which controls the motion of the particles.its momentum has uncertainty delta(p) , where p stands for momentum.

Hope this answer helps!