Quantum confinement effect of nanocrystalline GaN films prepared by pulsed-laser ablation under various Ar pressures

• Published in: Thin solid films Vol. 471; no. 1; pp. 273 - 276
• Main Authors: Yoon, Jong-Won, Sasaki, Takeshi, Roh, Cheong Hyun, Shim, Seung Hwan, Shim, Kwang Bo, Koshizaki, Naoto
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 2005; Elsevier Science
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Laser ablation; Laser deposition; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Optical properties; Physics; 79.20.D; Laser ablation; Optical properties; 78.66.J; Nanocrystalline-materials; Confinement; Inorganic compounds; Pressure effects; Gallium nitrides; Quantum effect; Crystal growth from vapors; XRD; SAED; Experimental study; Pulsed lasers; Thin films; Hexagonal lattices; Transmission electron microscopy; Wurtzite structure; Laser ablation technique; Absorption spectra; 78.66.J Laser ablation; Nanostructured materials; Nanocrystal; III-V semiconductors
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2004.06.123

Pulsed-laser deposition (PLD) was performed under various Ar pressures to prepare nanocrystalline GaN films without substrate heating or any post-annealing treatment. The X-ray diffraction (XRD) pattern and selected area electron diffraction indicated that the deposited films were hexagonal GaN with wurtzite structure. High-resolution transmission electron microscopic observation revealed that the particles in GaN films deposited in Ar ambient gas below 50 Pa were smaller than the exciton Bohr radius of GaN (11 nm). Large blueshifts in optical bandgap of the films deposited at lower Ar pressures were observed, indicating strong quantum confinement effects in small GaN particles.