Study of high resolution TEM images of nanoparticles either supported on amorphous films or embedded in a crystalline matrix

The contrast analysis of HREM images for nanoparticles supported in an amor phous substrate is studied. The particular case when these particles are em bedded in a crystalline matrix is discussed. It is demonstrated that, depen ding on the substrate thickness, the particle contrast can show contrast ar tifacts along their edges. In some cases for thick substrates the particle image can even disappear. The contrast observed from particles embedded in a crystalline structure can fluctuate from invisibility to highly contraste d Moire patterns.