Effect of carrier gas and substrate misorientation on the structural and optical properties of m-plane InGaN/GaN light-emitting diodes

• Published in: Journal of crystal growth Vol. 313; no. 1; pp. 1 - 7
• Main Authors: Farrell, R.M., Haeger, D.A., Chen, X., Iza, M., Hirai, A., Kelchner, K.M., Fujito, K., Chakraborty, A., Keller, S., DenBaars, S.P., Speck, J.S., Nakamura, S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.12.2010; Elsevier
• Subjects: A1. Crystal morphology; A3. Metalorganic chemical vapor deposition; Applied sciences; B1. Nitrides; B2. Semiconducting III–V materials; B3. Light emitting diodes; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Materials science; Methods of crystal growth; physics of crystal growth; Methods of deposition of films and coatings; film growth and epitaxy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Optoelectronic devices; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; B3. Light emitting diodes; B1. Nitrides; B2. Semiconducting III–V materials; A1. Crystal morphology; A3. Metalorganic chemical vapor deposition; Output power; High density; Electroluminescence; Gallium nitride; Surface states; B2. Semiconducting III-V materials; Thin films; Optical properties; Indium nitride; Silicon; Crystal morphology; Surface morphology; Quantum wells; Line widths; Light emitting diodes; Optoelectronic devices; Indium; MOCVD; Silicon additions; III-V compound; Growth mechanism; Nanostructured materials; III-V semiconductors
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2010.08.060

The properties of Si-doped GaN (GaN:Si) thin films and InGaN/GaN light-emitting diodes (LEDs) grown by metalorganic chemical vapor deposition on free-standing {1 0 1̄ 0} m-plane GaN substrates were investigated with regard to carrier gas and substrate misorientation toward the [0 0 0 1̄] c − direction. The surface morphology of the GaN:Si thin films and the LEDs was found to be strongly dependent on the choice of carrier gas and substrate misorientation. Growth of GaN:Si thin films on nominally on-axis substrates produced surfaces with a high density of four-sided pyramidal hillocks, regardless of the composition of the carrier gas. In contrast, growth of GaN:Si thin films on substrates with misorientation angles greater than 0.7° yielded moderately to severely faceted surfaces when grown with H 2 as the carrier gas and atomically smooth surfaces when grown with N 2 as the carrier gas. Although the surface morphology varied significantly with substrate misorientation, the average indium mole fraction in the InGaN-based quantum wells, the output power of the LEDs, the electroluminescence (EL) peak wavelength, and the EL linewidth showed little dependence on substrate misorientation. Substrates with misorientation angles of about 1° were successfully used to grow LEDs with improved surface morphology but similar optical properties, compared to LEDs grown on nominally on-axis substrates.