This paper describes an experimental study of thermal contact conductance enhancement enabled by carbon nanotube (CNT) arrays synthesized directly on silicon wafers using plasma-enhanced chemical vapor deposition. Testing based on the one-dimensional reference bar method occurred in a high-vacuum environment with radiation shielding, and temperature measurements were made with an infrared camera. Results from other thermal interface materials are presented, as well as combinations of these materials with CNT arrays. Dry CNT arrays produce a minimum thermal interface resistance of 19.8 mm(2) K/W, while the combination of a CNT array and a phase change material produces a minimum resistance of 5.2 mm(2) K/W. (c) 2005 Elsevier Ltd. All rights reserved.