The use of cryogenic temperatures (similar to 77 K) during An Schottky contact deposition onto n-GaAs produces an increase in barrier height from 0.73 eV for room temperature diodes to 0.82 eV. Not all Schottky metals show this enhancement - for example Pt and Ti do not show any significant change in barrier height whereas An, Pd and Ni show increases between 7 and 18%. We used X-ray reflectivity to show that the main difference between Au deposited at 77 K and room temperature is a decreased metal roughness while the interfacial roughness between the An and GaAs is basically the same. As the diodes are annealed to 300 T both the difference in barrier height and interfacial roughness is lost. This is a simple method with potential for improving the performance of GaAs metal-semiconductor-field-effect-transistors (MESFETs). (c) 2006 Elsevier B.V. All rights reserved.