The impact of RF-plasma power in carrier relaxation dynamics of unintentional doped GaN epitaxial layers grown by MBE
| Autor: | Prabir Pal, Arun Barvat, Nisha Prakash, Dilip K. Singh, K.K. Maurya, Kritika Anand, Suraj P. Khanna, Mukesh Jewariya, Sonachand Adhikari, Srinivasa Ragam |
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| Rok vydání: | 2016 |
| Předmět: |
Photoluminescence
Materials science chemistry.chemical_element 02 engineering and technology Epitaxy 01 natural sciences Inorganic Chemistry 0103 physical sciences Electrical and Electronic Engineering Physical and Theoretical Chemistry Gallium Spectroscopy 010302 applied physics business.industry Photoconductivity Organic Chemistry Doping Relaxation (NMR) 021001 nanoscience & nanotechnology Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials chemistry Optoelectronics 0210 nano-technology Luminescence business |
| Zdroj: | Optical Materials. 54:26-31 |
| ISSN: | 0925-3467 |
| DOI: | 10.1016/j.optmat.2016.02.012 |
| Popis: | In this work, unintentionally doped GaN samples were prepared on GaN template by radio frequency (RF)-plasma MBE technique using two different RF-plasma powers. Photoluminescence (PL), steady state photoconductivity (PC) and ultrafast optical pump-probe spectroscopy measurements have been carried out to characterize the samples. The effect of RF-plasma power towards unintentional doping and giving rise to yellow luminescence (YL) is discussed. Our PC measurements show relatively faster decay for sample grown with higher RF-plasma power. In addition, the ultrafast optical pump-probe spectroscopy results show the presence of various defect levels with different relaxation times. A faster ultrafast relaxation time from the conduction band to the closest defect level and conduction band to the next defect level was observed for the sample grown with higher plasma power. A comparatively low defect density and faster carrier relaxation observed in higher RF-plasma power grown samples is caused by lower impurities and gallium vacancies. The results imply that RF-plasma power is very important parameter for the growth of epitaxial GaN films and undesirable impurities and gallium vacancies might get incorporated in the epitaxial GaN films. |
| Databáze: | OpenAIRE |
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