Reversible change in electrical and optical properties in epitaxially grown Al-doped ZnO thin films

Abstract

Aluminum-doped ZnO ͑AZO͒ films were epitaxially grown on sapphire ͑0001͒ substrates using pulsed laser deposition. As-deposited AZO films had a low resistivity of 8.01ϫ 10 −4 ⍀ cm. However, after annealing at 450°C in air, the electrical resistivity of the AZO films increased to 1.97ϫ 10 −1 ⍀ cm because of a decrease in the carrier concentration. Subsequent annealing of the air-annealed AZO films in H 2 recovered the electrical conductivity of the AZO films. In addition, the conductivity change was reversible upon repeated air and H 2 annealing. A photoluminescence study showed that oxygen interstitial ͑O i Ј͒ is a critical material parameter allowing for the reversible control of the electrical conducting properties of AZO films.

Influence of the aluminum incorporation on the properties of electrodeposited ZnO thin films

“…Al-doped ZnO thin films have been synthesized by a variety of processes, including chemical spray technique [26], pulsed laser deposition technique [27], sol-gel dip-coating [28], reactive DC and RF sputtering [29] and electrochemical deposition (ECD) [30][31][32]. Among these methods, electrochemical deposition has the advantage of simplicity and ease of application for large area solar cells.…”

Electron emission of Au nanoparticles embedded in ZnO for highly conductive oxide

“…In order to reduce electric conductivity by increasing carrier concentration, IIIA dopants such as Al, [1][2][3][4][5] Ga, [6][7][8] and In, [9][10][11][12] have been incorporated into the ZnO lattice using several physical or chemical methods. In those studies of doped ZnO films, the carrier concentration reaches the range of 10 19 -10 20 cm À3 , the carrier mobility, however, is below 30 cm 2 /V s. An inherent problem in these highly doped ZnO films is that: increasing the dopant level for high carrier concentration lead to an increase in the point defect density, 13 which could also serve as scattering centers for electrons. Since electron mobility of those doped ZnO films is mainly determined by point defects (ionized impurities) and extended defects (grain boundaries), highly doped ZnO with dense point defects exhibits low electron mobility.…”

Enhanced infrared transmission of GZO film by rapid thermal annealing for Si thin film solar cells

“…On the other hand, both the Ga oxides and the lattice defects act as scattering centers for carrier transport 12–14. These oxides and/or lattice defects generally also act as optical absorption centers, which could decrease the film transmission in the UV and visible region 15–17. When the films are rapid‐thermally annealed at temperatures lower than 400°C, decomposition of the Ga oxides occurs and reduces the density of scattering defects 13.…”