Structural and optical investigation of nonpolar a-plane GaN grown by metal-organic chemical vapour deposition on r-plane sapphire by neutron irradiation

• Published in: Chinese physics B 2012-02, Vol.21 (2), p.531-535
• Main Author: 张金风 谷文萍 郝跃 张进成 周小伟 林志宇 毛维
• Format: Article
• Language: English
• Subjects: Atomic force microscopy; Chemical vapor deposition; Diffraction; Fittings; Gallium nitrides; Irradiation; Morphology; Neutron irradiation; Sapphire; 中子辐照; 光学调查; 化学气相沉积法; 平面结构; 有机金属; 氮化镓; 蓝宝石; 非极性
• ISSN: 1674-1056; 2058-3834; 1741-4199
• DOI: 10.1088/1674-1056/21/2/027802

Nonpolar （1150） a-plane GaN films are grown by metal-organic chemical vapour deposition （MOCVD） on r-plane （1102） sapphire. The samples are irradiated with neutrons under a dose of 1× 1015 cm-2. The surface morphology, the crystal defects and the optical properties of the samples before and after irradiation are analysed using atomic force microscopy （AFM）, high resolution X-ray diffraction （HRXRD） and photoluminescence （PL）. The AFM result shows deteriorated sample surface after the irradiation. Careful fitting of the XRD rocking curve is carried out to obtain the Lorentzian weight fraction. Broadening due to Lorentzian type is more obvious in the as-grown sample compared with that of the irradiated sample, indicating that more point defects appear in the irradiated sample. The variations of line width and intensity of the PL band edge emission peak are consistent with the XRD results. The activation energy decreases from 82.5 meV to 29.9 meV after irradiation by neutron.