作　　者： ; ; ; ; ; ; ; ; ; ;

机构地区： 中国科学院激发态物理重点实验室

出　　处： 《发光学报》 2006年第5期831-833,共3页

摘　　要： 利用射频等离子体辅助的分子束外延(P-MBE)技术在c面的蓝宝石衬底上生长了具有不同Mg含量(0≤x≤0.28)的六方相MgZnO合金薄膜,研究了该系列样品Raman频移的幅度与合金组分的对应关系,为MgZnO合金中Mg含量的确定提供了新的方法。在此基础上选择具有合适带宽的MgZnO合金作为垒层,制备了MgZnO/ZnO量子阱结构。在较高的光激发密度下,观测到了发光强度随激发密度的超线性增加,并将之归因于激子-激子碰撞引起的超辐射过程。 Hexagonal MgxZn1-xO alloy layers with 0≤x 〈0.3 have been grown by plasma-assisted molecular beam epitaxy on sapphire （006） substrates. Their crystal structures are characterized by X-ray diffraction spectroscopy. The resonant Raman spectra were measured using 325 nm line from He-Cd laser by backscattering geometry. The long wavelength frequencies of ZnO-like optical phonons measured in the resonant Raman spectra can be expressed as linear functions of x ： ω （LO） = （ 580 ＋ 147x） cm^ - 1. ZnO/Mg0.12 Zn0.88 O singlequantum well （SQW） with 1.5 nm ZnO well width was grown on sapphire substrate. In the PL spectra at 5 K, P band located at 3. 371 eV was observed. At excitation densities higher than 76 kW/cm^2, the P band shows a typical super linear increase characteristic. With increasing the excitation density further, the P band converges gradually at the saturation value of 3. 354 eV with significant narrowing. It was attributed to the gradually enhanced exciton-exciton scattering. The integrated emission intensity versus excitation density follows the relation of Iex^3.13. This superlinear increase indicates the typical properties of a super-radiation recombination.

关 键 词： 合金 光谱 量子阱 超辐射

领　　域： [理学] [理学] [理学] [理学]