Application of low resistivity Ga-doped ZnO films to transparent electromagnetic interference shielding material

Low-sheet-resistance Ga-doped ZnO films with thickness between about 0.3 and 2 mu m were prepared on glass substrates by ion-plating system, which can be also deposited on large-area substrate with a size of 1 m(2). The electromagnetic interference (EMI) shielding effectiveness and transparency of the films were investigated. Hall effect measurements showed that a decrease in resistivity with thickness causes an effective decrease in sheet resistance of the films. With decreasing sheet resistance, the EMI shielding effectiveness of the films at a frequency of 2.45 GHz increased, and the highest shielding effectiveness was 47.4 dB. All of the films demonstrated visible transmission of more than 70%. (C) 2008 Elsevier B.V. All rights reserved.