应力和掺杂对Mg:GaN薄膜光致发光光谱影响的研究

对化学气相沉积(MOCVD)法在宝石衬底上生长的Mg掺杂GaN薄膜的表面及其GaN缓冲层的光致发光(PL)光谱进行了测量，用Raman光谱和x射线衍射(XRD)对GaN薄膜中的应力进行确定，通过PL光谱中的中性束缚激子跃迁能量的变化确定薄膜中应力的影响，从而研究Mg掺杂对p型GaN的DAP跃迁影响规律. 关键词： 光致发光 应力 Raman光谱

Effects of strain and Mg-dopant on the photoluminescencespectra in p-type GaN

The photoluminescence (PL) spectra of Mg-doped GaN on sapphire have been measured at 12K. The residual strain induced by the mismatch of the lattice constants and thermal expansion between GaN epilayers and substrates have been investigated by micro-Raman scattering and x-ray diffraction. Redshifts of the ultraviolet PL bands were observed in Mg-doped GaN after annealing in nitrogen ambient, which may be related to the carrier concentration and the strain in the epilayers. For heavily Mg-doped GaN films, the hole concentration in GaN, which shifts the PL peaks, is the dominant influence, whereas the strain is comparatively secondary.