Ion-induced damage and intermixing was evaluated in InGaN/GaN multi-quantum wells (MQWs) using 35 keV N(+) implantation at room temperature. In situ ion channeling measurements show that damage builds up with a similar trend for In and Ga atoms, with a high threshold for amorphization. The extended defects induced during the implantation, basal and prismatic stacking faults, are uniformly distr...

Single-crystal X-ray diffraction experiments on e-quartz at pressures to 15 GPa reveal structural instabilities that result in its gradual transition to an amorphous state. With increasing pressure the average Si-O distance ( ~ 1.61 + 0.01/~) and S i O 4 tetrahedral volume (,,~2.14 ___ 0.02.~ 3) remain constant. Compression of e-quartz results from a dramatic decrease in Si-O-Si angle and corre...

While a significant fraction of silicate dust in stellar winds has a crystalline structure, in the interstellar medium nearly all of it is amorphous. One possible explanation for this observation is the amorphization of crystalline silicates by relatively ‘‘low’’ energy, heavy-ion cosmic rays. Here we present the results of multiple laboratory experiments showing that single-crystal synthetic f...