The grain size effects on the photoluminescence of ZnO/α-Al2O3 grown by radio-frequency magnetron sputtering

Abstract

ZnO thin films were epitaxially grown on α-Al2O3 (0001) substrate by radio-frequency (rf) magnetron sputtering. Among the ZnO films deposited at 550 °C, the film deposited at 80 W has the narrowest full width half maximum (FWHM) of x-ray diffraction (XRD) θ-rocking curve, 0.16°, indicating a highly c-axis oriented columnar structure. The FWHM of XRD θ-rocking curve of the ZnO film deposited at 120 W and 600 °C was 0.13° with a minimum channeling yield, 4%–5%. In photoluminescence (PL) measurement, only the sharp near band edge emission was observed at room temperature (RT). The FWHM of PL peak was decreased from 133 to 89 meV as rf power increased from 80 to 120 W at 550 °C, and that of film deposited at 120 W and 600 °C showed 76 meV which is lower value than any other ever reported. These PL results were somewhat opposite to that of XRD. From transmission electron microscopy analysis, grain size and defects were found to affect the PL properties. In this study, the PL property of undoped ZnO thin films is discussed in terms of the crystalline structure and the size of grain.

High optical quality ZnO epilayers grown on sapphire substrates by reactive magnetron sputtering of zinc target

“…The half-width of the band edge peak for the epilayer deposited at 600 1C is $96 meV, which is significantly smaller than the value of $157 meV for the epilayer deposited at 300 1C. The FWHM of $96 meV for the room temperature band edge PL peak is quite comparable to the corresponding results reported for high-quality ZnO epilayers grown by sputtering [13,14,17], PLD [38], MOCVD [39] and MBE [8] techniques. As typical examples, PL width values of 117 meV [8] and 106 meV [16] have been reported, for MBE-grown ZnO epilayers (with (0 0 0 2) rocking curve width $0.0051) and homo-epitaxial ZnO grown by magnetron sputtering (with (0 0 0 2) rocking curve width $10 arcsec), respectively.…”

“…High-quality ZnO epilayers have usually been grown on crystalline substrates, such as sapphire by PLD [5][6][7], MBE [8][9][10] and MOCVD [11,12]. In recent years, there has been an increasing interest in the growth of ZnO epilayers by sputtering [13][14][15][16][17][18][19][20][21][22]. This is owing to the advantages of sputtering in terms of versatility, large-area deposition, low cost, high deposition rates and scalability.…”

Size-dependence of LaF3:Eu3+nanocrystals on Eu3+photo-luminescence intensity

“…Therefore the decreasing Eu 3+ luminescence with more CTAB concentration than 0.006 mol/L can definitively be understood by the fact that the size of LaF 3 :Eu 3+ nanocrystals was decreased (See Fig.2 and 8). The similar tendency for nanomaterials was reported previously for nanophosphors with lower density of defects [17,18]. …”

Titanium Oxide Thin Film Preparation by Pulsed Laser Deposition Method Using a Powder Target

“…Physical vapor deposition (PVD) refers to a variety of well-known film deposition methods, and thier deposition mechanisms have been thoroughly studied [1][2][3][4][5][6][7][8][9][10][11]. In particular, pulsed laser deposition (PLD) is a widely used technique for the deposition of thin films because of its advantages such as a simple system setup, operability under a wide range of deposition conditions, wider choice of materials offered, and higher instantaneous deposition rates.…”