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Preparation and characteristics of the In-doped ZnO thin films and the n-ZnO:In/p-Si heterojunctions for optoelectronic switch n-ZnO:In/p-Si heterojunctions have been fabricated by sputter deposition of n-ZnO:In on p-Si substrates. The lowest resistivity n-ZnO:In film was obtained at a substrate temperature of 150$^o$C using a ZnO target doped with 2 wt\% In$_2$O$_3$. At substrate temperature above 300$^o$C the resistivity of the film increases as the carrier concentration decreases. This implies a significant decrease in the donor impurity, which is ascribed to evaporation of the indium during film growth. . | VNU Journal of Science Mathematics - Physics 26 2010 9-16 Preparation and characteristics of the In-doped ZnO thin films and the n-ZnO In p-Si heterojunctions for optoelectronic switch Ta Dinh Canh Nguyen Viet Tuyen Nguyen Ngoc Long Vo Ly Thanh Ha Faculty of Physics Hanoi University of Science VNU 334 Nguyen Trai Thanh Xuan Hanoi Vietnam Received 10 February 2010 Abstract. n-ZnO In p-Si heterojunctions have been fabricated by sputter deposition of n-ZnO In on p-Si substrates. The lowest resistivity n-ZnO In film was obtained at a substrate temperature of 150 C using a ZnO target doped with 2 wt IU2C 3. At substrate temperature above 300 C the resistivity of the film increases as the carrier concentration decreases . This implies a significant decrease in the donor impurity which is ascribed to evaporation of the indium during film growth. The wavelength dependent properties of the photo-response for the heterojunction were investigated in detail by studying the effect of light illumination on current - voltage I-V characteristic photocurrent spectra at room temperature. From the photocurrent spectra it was observed that the visible photons are absorbed in the p-Si layer while ultraviolet UV photons are absorbed in the depleted n-ZnO In film under reverse bias conditions. The properties of ZnO In films prepared by r.f. magnetron sputtering are good enough to be used in photoelectrical devices. Keywords n-ZnO In p-Si Heterojunction R.F. magnetron sputtering Current-voltage characteristic Photocurrent. 1. Introduction Zinc oxide ZnO films have been extensively studied for practical application including bulk acoustic resonators 1 grating-coupled wave-guard filters 2 acoustic-electric devices 3 transparent electrode materials for various electronic devices such as solar cells electroluminescence displays etc. 4 6 . Heterojunction solar cells consisting of a wide band gap transparent conductive oxide TCO on a crystal silicon Si wafer have a number of potential .
