Systems, apparatuses, and methods relating to memory devices and packaging are described. A device, such as a dual inline memory module (DIMM) or other electronic device package, may include a substrate with a layer of graphene configured to conduct thermal energy (e.g., heat) away from components mounted or affixed to the substrate. In some examples, a DIMM includes an uppermost or top layer of graphene that is exposed to the air and configured to allow connection of memory devices (e.g., DRAMs) to be soldered to the conducting pads of the substrate. The graphene may be in contact with parts of the memory device other than the electrical connections with the conducting pads and may thus be configured as a heat sink for the device. Other thin, conductive layers of may be used in addition to or as an alternative to graphene. Graphene may be complementary to other heat sink mechanisms.