  Discovery of two-dimensional materials with unique electronic, superior
optoelectronic or intrinsic magnetic order have triggered worldwide interests
among the fields of material science, condensed matter physics and device
physics. Vertically stacking of two-dimensional materials with distinct
electronic and optical as well as magnetic properties enables to create a large
variety of van der Waals heterostructures. The diverse properties of the
vertical heterostructures open up unprecedented opportunities for various kinds
of device applications, e.g. vertical field effect transistors, ultrasensitive
infrared photodetectors, spin-filtering devices and so on, which are
inaccessible in the conventional material heterostructures. Here, we review the
current status of vertical heterostructures device applications in vertical
transistors, infrared photodetectors and spintronic memory/transistors. The
relevant challenges for achieving high-performance devices are presented. We
also provide outlook on future development of vertical heterostructure devices
with integrated electronic and optoelectronic as well as spintronic
functinalities.
