IEEE Trans Ultrason Ferroelectr Freq Control. 2014 Feb;61(2):364-8. doi: 10.1109/TUFFC.2014.6722620.
A square lattice of shallow, noncylindrical holes in GaAs is shown to act as a phononic crystal (PnC) reflector. The holes are produced by wet-etching a GaAs substrate using a citric acid:H2O2 etching procedure and a photolithographed array pattern. Although nonuniform and asymmetric etch rates limit the depth and shape of the phononic crystal holes, the matrix acts as a PnC, as demonstrated by insertion loss measurements together with interferometric imaging of surface acoustic waves propagating on the GaAs surface. The measured vertical displacement induced by surface phonons compares favorably with finite-difference time-domain simulations of a PnC with rounded-square holes.
砷化镓中浅非圆柱形孔的正方形晶格被证明可以作为声子晶体（PnC）反射器。这些孔是通过使用柠檬酸：H2O2 蚀刻程序和光刻阵列图案对 GaAs 衬底进行湿法蚀刻产生的。尽管不均匀和不对称的蚀刻速率限制了声子晶体孔的深度和形状，但该基质作为声子晶体，这一点通过表面声波在 GaAs 表面传播的插入损耗测量以及干涉成像来证明。表面声子引起的测量垂直位移与具有圆形方形孔的 PnC 的有限差分时域模拟非常吻合。
