Amorphous GaN films deposited by DC sputtering

作者：Jia Lu; Pan Xiaojun; Zhang Zhenxing; Xie Erqing^*

来源：Optoelectronics and Advanced Materials-Rapid Communications, 2008, 2(2): 71-75.

• amorphous GaN
• DC sputtering
• absorption

The films are deposited by direct current (DC) planar magnetron sputtering at different argon concentration in the sputtering gas (defined as Ar%). X-ray diffraction (XRD), Fourier Transform Infrared spectra (FTIR) and Raman spectra indicate that the films are amorphous. The main absorption of the FTIR is due to Ga-N bond stretching vibration. Spectroscopic Ellipsometry (SE) and UV-VIS spectra show that the refractive index of the a-GaN is very similar to that of crystalline GaN (c-GaN). When increasing Ar concentration from 10 % to 40 %, the thicknesses of the films change from 565.6 nm to 1526.1 nm linearly, which implies that Ar promotes the deposition rate. The Tauc band gap of the film deposited at lower Ar (similar to 0%) is 3.9 eV, which is much larger than that of c-GaN, due to the structural disorder. While the films deposited at higher Ar%, the band gaps become much smaller (3.3 eV similar to 2.8 eV), probably because of more excess Ga in the films. The band tails extending to lower energies are modeled, and the parameters indicate that a-GaN films have a wider absorption tail than that of c-GaN film.

• 出版日期2008
• 单位兰州大学