A heat spreader includes a bottom wall (12) and a cover (14) hermetically
connected to the bottom wall. Cooperatively the bottom wall and the cover
define a space (11) therebetween for receiving a working fluid therein. A
wick structure (15) is received in the space and thermally interconnects
the bottom wall and the cover. The wick structure includes at least a
carbon nanotube array, which can conduct heat from the bottom wall to the
cover and draw condensed liquid of the working fluid from the cover
toward the bottom wall.