(N/A) Matter waves,also known as de Broglie waves,are the waves associated with moving particles of matter (such as electrons,protons,or neutrons). According to the de Broglie hypothesis,any moving particle with momentum $p$ has an associated wavelength $\lambda$ given by $\lambda = h/p$,where $h$ is Planck's constant.
Devices that employ the use of matter waves include:
$1$. Electron Microscope: It uses the wave nature of electrons to achieve much higher resolution than optical microscopes.
$2$. Electron Diffraction Apparatus: Used to study the crystal structure of materials by observing the diffraction patterns of electrons.