Correlations between electrical and optical properties for OMVPE InN

• Published in: Journal of crystal growth 2004-01, Vol.261 (2), p.275-279
• Main Authors: Yamamoto, A., Sugita, K., Takatsuka, H., Hashimoto, A., Davydov, V.Yu
• Format: Article
• Language: English
• Subjects: A3. Metalorganic vapor phase epitaxy; B1. Nitrides; B2. Semiconducting III–V materials
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2003.11.082

An experimental study has been made of correlations between electrical and optical properties for OMVPE InN grown on sapphire substrate. Carrier concentration for a grown film is found to decrease with increasing growth temperature and shows the lowest value 5.8×10 18 cm −3 at 600°C. A strong photoluminescence (PL) with a peak energy of 0.7–0.8 eV is observed at room temperature. As a general trend, PL peak energy and optical absorption edge increase with increasing carrier concentration (Burstein–Moss shift). For relatively thick films with large grains, grown at a relatively high temperature, a discrepancy is found between carrier concentration obtained by Hall measurement and PL data. Such samples show a PL spectrum with a lower peak energy and a smaller FWHM in spite of a higher carrier concentration. Although Hall measurement gives a carrier concentration as high as 2.3×10 19 cm −3 for the sample grown at 620°C, this sample should have a much lower carrier concentration because the PL peak energy is lower than that for the sample with the lowest carrier concentration 5.8×10 18 cm −3. These results show that the optimum growth temperature is higher than 600°C determined from the electrical characterisation.