May I humbly recommend a terrific summary of the Davisson Germer experiment? [1] It is a great biographical summary of developing the experiment itself, with some experimental data not published elsewhere online of the electron diffraction phenomenon.
The design of the experiment is often as important as the result. It opens up a whole avenue of discovery as the same technique is applied to other problems.
[1] https://physicstoday.scitation.org/doi/10.1063/1.3001830