Nanoscientists Provide New Picture of Semiconductor Material
Cubic gallium nitride surface studied afresh...
 

Written by Arthur R. Smith, 01.01.2006

The surface of zinc-blende (cubic) gallium nitride (001) has been a topic of considerable interest due to the importance of gallium nitride in general and the fact that only the cubic phase is truly compatible with conventional III-V semiconductor materials. Recent research by the NSNM NIRT team and a Spanish collaborator was recently published in Physical Review Letters, showing the intrinsic surface structure of this material. As it turns out, the structure appears to be yet a bit different than even the most prevailing and accepted theory states. In particular, researchers experimentally found that the fundamental structure was 4x3. A 4x1 model however, was used to model the data with surprisingly good agreement, all accept for the 3x periodicity along one of the crystal axes. Nonetheless, theorists will need to re-examine the theory to find out what may be the cause of the 3x.


Despite the small discrepancy however, between the new experiment and accepted 4x1 theory, the agreement between them is impressive, considering that previous surface images of cubic GaN(001) published about a decade ago by other researchers were completely different from the 4x1 model later accepted theoretically in 1998. The reason for that complete disagreement had to do with impurities in the earlier researchers' experiment. Now, we may say that the new experiment is in 99% agreement with the current theory, with the 3x vs. 1x discrepancy noted.


For the Physical Review Letter article, see "Scanning Tunneling Microscopy and Surface Simulation of Zinc-Blende GaN(001)Intrinsic 4x Reconstruction: Linear Gallium Tetramers?".


For the Research News story, see "Nanoscientists Provide New Picture of Semiconductor Material".