Band gap energy of pure and Al-doped ZnO thin films

Pulsed laser deposition (PLD) technique is used to deposit pure and Al-doped ZnO thin films at different temperatures on glass substrates. From the transmission data from optical spectroscopy the band gap energy Eg of the films is derived. The dependences of Eg on the deposition temperatures of the pure and Al-doped ZnO films are different. The band gap energy of the pure ZnO increases and saturates with temperature. However, Eg of Al-doped ZnO shows an exponential decrease. Refractive indices of 1.9–2.1 in the VIS are determined by the spectroscopic ellipsometry (SE). Photoluminescence (PL) data reveal the strong near band emission by increasing the deposition temperature. # 2003 Elsevier Ltd. All rights reserved.

[1]  M. Graef,et al.  Microstructural characterization of α‐GaN films grown on sapphire by organometallic vapor phase epitaxy , 1995 .

[2]  S. Choopun,et al.  Pulsed laser deposition and processing of wide band gap semiconductors and related materials , 1999 .

[3]  S. Y. Kim,et al.  Simultaneous determination of dispersion relation and depth profile of thorium fluoride thin film by spectroscopic ellipsometry , 1988 .

[4]  H. Morkoç,et al.  NEAR ULTRAVIOLET LUMINESCENCE OF BE DOPED GAN GROWN BY REACTIVE MOLECULAR BEAM EPITAXY USING AMMONIA , 1996 .

[5]  T. Moustakas,et al.  Blue‐violet light emitting gallium nitride p‐n junctions grown by electron cyclotron resonance‐assisted molecular beam epitaxy , 1995 .

[6]  F. Shan,et al.  Optical properties of As doped ZnO thin films prepared by pulsed laser deposition technique , 2004 .

[7]  David C. Look,et al.  Recent Advances in ZnO Materials and Devices , 2001 .

[8]  G. Hubler,et al.  Pulsed Laser Deposition of Thin Films , 2003, Handbook of Laser Technology and Applications.

[9]  M. Asif Khan,et al.  Atomic layer epitaxy of GaN over sapphire using switched metalorganic chemical vapor deposition , 1992 .

[10]  Hamberg,et al.  Band-gap tailoring of ZnO by means of heavy Al doping. , 1988, Physical review. B, Condensed matter.

[11]  Manijeh Razeghi,et al.  High quality AIN and GaN epilayers grown on (00⋅1) sapphire, (100), and (111) silicon substrates , 1995 .

[12]  N. El-Masry,et al.  Growth of device quality GaN at 550 °C by atomic layer epitaxy , 1995 .

[13]  Klaus Reimann,et al.  Band gaps, crystal-field splitting, spin-orbit coupling, and exciton binding energies in ZnO under hydrostatic pressure , 1995 .

[14]  J A Dobrowolski,et al.  Determination of optical constants of thin film coating materials based on inverse synthesis. , 1982, Applied optics.