GaN1-xPx三元合金的光学与结构特性

对采用金属有机化学气相淀积(MOCVD)技术生长的GaN1-xPx三元合金进行了低温光致发光(PL)和X射线衍射(XRD)测试分析，与来自GaN层的带边发射相比，P的摩尔分数比为0．03，0．11和0．15的GaN1-xPx的光致发光峰分别呈现出了73meV，78meV和100meV的红移，文中将这种红移归因于GaN1-xPx合金具有大的带隙能量弯曲系数。X射线衍射结果表明GaN1-xPx三元合金仍为六方结构晶体，且随着P组份比的增加，GaN1-xPx合金的(0002)衍射峰逐渐向小角度方向移动，即晶格常量变大，同时，(0002)衍射峰谱线不断宽化，说明由于替位式P原子的不规则分布以及部分间隙P原子的影响造成了GaN1-xPx样品的晶格畸变。在GaN1-xPx的光致发光谱及X射线衍射谱中均未观测到相应的有关GaP的峰，表明所生长的高P含量的GaN1-xPx三元合金没有产生明显的相分离。

Optical and Structural Properties of GaN1-xPx Ternary Alloys

X-ray diffraction (XRD) and Photoluminescence (PL) spectra for a series of high phosphorus compositional GaN_ 1-x P_ x films grown by means of light-radiation heating,low-pressure metal-organic chemical vapor deposition have been investigated. Photoluminescence spectra for GaN_ 1-x P_ x layers with P/N composition ratios of 15%,11% and 3% show the red-shifts of 100 meV,78 meV and 73 meV,respectively,from that of GaN due to a large bowing of band gap energy. X-ray diffraction results show that (0002) peaks of GaN_ 1-x P_ x samples have shifted to smaller angles compared with that of an undoped GaN sample,and the linewidth of the (0002) peak becomes broader with increasing P composition in the samples,indicating that the crystal lattice distortion is produced due to the P incorporation into the GaN host lattice. No peak related to GaP is observed in X-ray diffraction and photoluminescence spectra,which indicates that the phase separation between GaN and GaP has not occurred in our GaN_ 1-x P_ x samples.