Influences of Substrate and Annealing on the Structural and Optical Properties and Photoluminescence of Nanocrystalline ZnO Films Prepared by Plasma Assisted Pulsed Laser Deposition

Abstract

Single-crystalline silicon, amorphous quartz, and single-crystalline sapphire were used as the substrates for the deposition of nanocrystalline zinc oxide (nc-ZnO) thin films by plasma assisted pulsed laser deposition from metallic zinc at low temperature below 80 °C, and a postdeposition annealing process was performed for the deposited nc-ZnO thin films. The influences of substrate and annealing on the structural and optical properties as well as the photoluminescence of the prepared nc-ZnO thin films were studied. Raman spectroscopy and Fourier-transform infrared spectroscopy measurements reveal the wurtzite ZnO phase in the films. X-ray diffraction results indicate the nanocrystalline structure of the films with c axis perpendicular to substrates. Optical characterization shows that the prepared films have an ultraviolet (UV) absorption edge near 380 nm with a direct band gap of about 3.25 eV. The prepared films emit predominantly UV photoluminescence at light excitation. The structure and properties of the films are dependent on substrates and the annealing process has different influences for the films deposited on different substrates.

Property–Performance Control of Multidimensional, Hierarchical, Single‐Crystalline ZnO Nanoarchitectures

“…The diffraction peaks at 2q = 31.80, 34.45, 36.24, 47.56 and 56.698 are ascribed to the (100), (002), (101), (102) and (110) crystal planes of the hexagonal wurtzite structure of ZnO, respectively. [14,34] In comparison with the peak of the bulk ZnO counterpart at 440 cm À1 , this peak shows a slight redshift. In addition, a small diffraction peak at 2q = 338 appearing in all of the spectra originates from the Si substrates.…”

“…along the [0001] direction presumably originates from the extremely anisotropic crystal structure of ZnO; the polar (0002) crystal plane of ZnO has a higher surface energy than any other low-index crystallographic planes, such as the ð11 2 À 0Þand ð01 1 À 0Þ planes. [14,21] For sample A1, pronounced diffraction peaks at 2q = 38.41 and 44.628, attributed to cubic gold, are observed, which suggests that the length and thickness of sample A1 are smaller than those of samples A2 and A3. XRD patterns of samples A1-A3 are presented in Figure 3 a.…”

Self-organized ZnO nanodot arrays: Effective control using SiNx interlayers and low-temperature plasmas

“…The exciton binding energy of ZnO (60 meV) is significantly higher than that of GaN (25 meV), which enables ZnO to emit short-wavelength light more efficiently even at room temperature. [1][2][3][4] Recently, a broad range of deposition methods have been developed to prepare various ZnO nanostructures, such as nanowires, nanorods, nanobelts, nanopins, nanorings. [5][6][7][8][9] However, only a few research works have been focused on the preparation of zero-dimensional ZnO nanodots.…”

Optoelectronic properties of ZnO film on silicon after SF6 plasma treatment and milliseconds annealing

“…8 Recently, we have utilised the plasma assisted reactive pulsed laser deposition to fabricate n-type nanocrystalline ZnO films on various substrates. 3,9 Keeping in mind the application aspects of ZnO thin films, a cost-effective and highthroughput process for TCO fabrication is required. In this letter, we present a highly-effective doping technique for ZnO films by fluoridation, utilizing plasma immersion ion implantation (PIII) of SF 6 , and subsequent millisecond range flash lamp annealing (FLA).…”

“…The deposition temperature did not exceed 80 C. A detailed description of the experimental equipment and the deposition procedure has been previously provided. 9 After deposition the samples were annealed by millisecond range FLA (35-50 J cm À2 ) in either argon or air atmosphere. 10,11 N-type doping of deposited ZnO was made by fluorination of the near surface region using SF 6 plasma.…”