Junction properties of nitrogen-doped ZnO thin films

ZnO-based p-n homojunctions, comprised of N-doped p-type ZnO and Al-doped n-type ZnO layers, were fabricated on n-Si substrates by atmospheric pressure mist chemical vapor deposition. In/Au metals were deposited oil the top of the p-ZnO layer and oil the bottom of the n-Si substrate to form Ohmic contacts. The n-Si substrate could serve as a good electrode. The current-voltage measurements at room temperature showed apparent rectifying behavior for the ZnO p-n homojunction, with a turn-on voltage of about 3.8 V under forward bias and a hard breakdown under reverse bias. The time-dependent instability after fabrication was attributed to the degradation of p-type conducting of the ZnO:N layer. (C) 2008 WILEY-VCH Veriag GmbH & Co. KGaA, Weinheim.