Acoustic power gain induced by 2D electron drifting

In this work, amplification of surface acoustic waves (SAWs) by electron drift in a nanometer-scale two-dimensional electron gas (2DEG) is analyzed analytically. We compare the amount of acoustic power gain per SAW radian produced by electron drift in a bulk GaN thin film layer and in a GaN-based 2DEG layer. Calculations suggest that acoustic amplification in a 2DEG is independent on the SAW frequency while only a very narrow bandwidth of SAWs could be amplified in bulk. Furthermore, the peak power gain per SAW radian occurs at a more practical carrier density for a 2DEG than for a bulk material.