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Probing the correlation between structure, carrier dynamics and defect states of epitaxial GaN film on (11(2)over-bar0) sapphire grown by rf-molecular beam epitaxy

IR@NPL: CSIR-National Physical Laboratory, New Delhi

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Title Probing the correlation between structure, carrier dynamics and defect states of epitaxial GaN film on (11(2)over-bar0) sapphire grown by rf-molecular beam epitaxy
 
Creator Krishna, T. C. Shibin
Aggarwal, Neha
Reddy, G. Anurag
Dugar, Palak
Mishra, Monu
Goswami, Lalit
Dilawar, Nita
Kumar, Mahesh
Maurya, K. K.
Gupta, Govind
 
Subject Chemistry
 
Description A systematic study has been performed to correlate structural, optical and electrical properties with defect states in the GaN films grown on a-plane (11 (2) over bar0) sapphire substrate via rf-plasma molecular beam epitaxy. Morphological analysis reveals the presence of small lateral size (30-70 nm) hexagonally shaped V-pits on the GaN films. These V-defects possibly contribute as the main source of non-radiative decay. High resolution X-ray diffraction reveals highly single crystalline GaN film grown on a-plane sapphire substrate where the threading dislocations are the cause of V-defects in the film. Photoluminescence measurement shows a highly luminescence band to band emission of GaN film at 3.41 eV along with a broad defect band emission centered at 2.2 eV. A detailed optical and electrical analysis has been carried out to study the defect states and related carrier dynamics for determining the efficacy of the film for device fabrication. The variation in the low temperature current voltage measurements confirms the presence of deep level defects in the mid-band gap region while transient spectroscopy shows that non radiative decay is the dominant relaxation mechanism for the photo excited-carriers from these defect states.
 
Publisher Royal Society of Chemistry
 
Date 2015
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://npl.csircentral.net/1958/1/265.pdf
Krishna, T. C. Shibin and Aggarwal, Neha and Reddy, G. Anurag and Dugar, Palak and Mishra, Monu and Goswami, Lalit and Dilawar, Nita and Kumar, Mahesh and Maurya, K. K. and Gupta, Govind (2015) Probing the correlation between structure, carrier dynamics and defect states of epitaxial GaN film on (11(2)over-bar0) sapphire grown by rf-molecular beam epitaxy. RSC Advances, 5 (89). pp. 73261-73267. ISSN 2046-2069
 
Relation http://npl.csircentral.net/1958/