Efforts have been made earlier (Arshak et al., 2002; Hikita et al., 1995; Lepp vuori et al., 1995; Ling et al., 2001; Ohya et al., 1998; Raffaelle et al., 1999; Ruda et al., 1997; Ryu et al., 2000) to fabricate pn-junctions using thin film technologies. Ohya et al. (1998) reported a pn-contact made from p-type semiconductor NiO film and n-type semiconductor ZnO film. The oxides semiconductor films have been prepared by a liquid phase method. The ZnO/NiO film provided a pn-contact interface and exhibited typical rectifying I-V characteristics. Other techniques such as electrochemical deposition of thin films were used to fabricate pn-junctions from n-type CdS and p-type copper indium diselenide (CIS) (Raffaelle et al., 1999). Homostructural pn-junctions with ZnO on GaAs substrates have been synthesized by pulsed laser ablation (Ryu et al., 2000), where As-doped ZnO films have been used for the p-type sides and Al-doped ZnO films for the n-type sides of pn-junctions.

Most of the pn-interfaces have been investigated with respect to gas sensing devices (Hikita et al., 1995; Ling et al., 2001) and solar cells (Lepp vuori et al., 1995; Ruda et al., 1997). Very few attempts have been made to use thin film pn-junctions for ?-ray dosimetry application (Arshak et al., 2002). The pn-junctions of an Al/S/CuPc/Al prepared by thermal vacuum deposition have been exposed to ?-radiation (Arshak et al., 2002). These pn-junctions exhibited...