  Technological advancement towards the quantum era requires secure
communication, quantum computation, and ultra-sensitive sensing capabilities.
Layered quantum materials (LQMs) have remarkable optoelectronic and quantum
properties that can usher us into the quantum era. Electron microscopy is the
tool of choice for measuring these LQMs at an atomic and nanometer scale. On
the other hand, electron-irradiation of LQMs can modify various material
properties, including the creation of structural defects. We review different
types of structural defects, as well as electron elastic- and
inelastic-scattering induced processes. Controlled modification of
optoelectronic and quantum properties of LQMs using electron-irradiation,
including creation of single photon emitters is discussed. Protection of
electron-irradiation induced damage of LQMs via encapsulation by other layered
materials is encouraged. We finally give insights into challenges and
opportunities, including creating novel structures using an electron beam.

Mesoscale and Nanoscale Physics;Materials Science