Structural, morphological, optical and electrical characterization of InGaN/GaN MQW structures for optoelectronic applications

K. Prabakaran (1) , M. Jayasakthi (1) , S. Surender (1) , S. Pradeep (1) , S. Sanjay (1) , R. Ramesh (2) , M. Balaji (3) , Nicolas Gautier (4) , K. Baskar (1, 5)

1 Crystal Growth Centre [Chennai]
2 Aalto University
3 University of Madras
4 IMN - Institut des Matériaux Jean Rouxel
5 Manonmaniam Sundaranar university (INDIA)

Mixed Ti x Si 1−x O 2 oxide can exhibit a partial phase separation of the TiO 2 and SiO 2 phases at the atomic level. The quantification of TiO 2-SiO 2 mixing in the amorphous material is complicated and was so far done mostly by infrared spectroscopy. We developed a new approach to the fitting of X-ray photoelectron spectroscopy data for the quantification of partial phase separation in amorphous Ti x Si 1−x O 2 thin films deposited by plasma enhanced chemical vapour deposition. Several fitting constraints reducing the total number of degrees of freedom in the fits and thus the fit uncertainty were obtained by using core electron binding energies predicted by density functional theory calculations on Ti x Si 1−x O 2 amorphous supercells. Consequently, a decomposition of the O 1s peak into TiO 2 , SiO 2 and mixed components was possible. The component areas ratios were compared with the ratios predicted by older theoretical models based on the atomic environment statistics and we also developed several new models corresponding to more realistic atomic structure and partial mixing. Based on the comparison we conclude that the studied films are mostly disordered, with only a moderate phase separation.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

K. Prabakaran, M. Jayasakthi, S. Surender, S. Pradeep, S. Sanjay, et al.. Structural, morphological, optical and electrical characterization of InGaN/GaN MQW structures for optoelectronic applications. Applied Surface Science, 2019, 476, pp.993-999. ⟨10.1016/j.apsusc.2019.01.156⟩. ⟨hal-02079849⟩