No point saying the electron can be this and that . Got to have the evidence just like photoelectric effect expt. Here electrons are fired at carbon atoms (acting as diffraction grating )and diffraction patterns emerged. Compared that form by electron to that by Xray. The results were true.. the electron wave produces diffraction pattern just like the X-rays (waves). Look at the diffraction rings. Which is particle (electrons) and which is wave (x-ray) ?