InGaN薄膜的紫外共振喇曼散射

利用325nm紫外光激发，对不同组分的In_xGa_1-xN薄膜的喇曼散射谱进行了研究.在光子能量大于带隙的情况下，观察到显著增强的二阶A₁(LO)声子散射峰.二阶LO声子峰都从一阶LO声子的二倍处向高能方向移动，移动量随样品In组分的增加而增大，认为是带内Frhlich相互作用决定的多共振效应引起的.分析了一阶LO声子散射频率和峰型与In组分的关系.在喇曼谱中观察到样品存在相分离现象，并与X射线衍射的实验结果进行关键词：xGa_1-xN合金')" href="#">In_xGa_1-xN合金紫外共振喇曼散射二阶声子相分离

Ultraviolet resonant Raman scattering in InGaN films

Ultraviolet Raman scattering spectra of In_xGa_1-xN films with different In compositions were investigated using 325nm laser line. For photon energy above the energy gap, strong enhanced 2A₁(LO)phonon scattering lines were observed. Four 2LO peaks shift from twice the energy of the first-order LO peak, to the high energy end and the shifts increase with In contents in the samples. It is attributed to the multiple resonance resulting from intraband-Frhlich interaction. The composition dependence of LO phonon mode frequency and line shape was analysed. The phase separation was observed in Raman spectra and compared with the data of X-ray diffraction. Furthermore, the E₂ phonon combination mode of In_xGa_1-xN was observed at about 1310cm^-1.