Growth and Properties of Sn-Doped ZnO Nanowires for Heterojunction Diode Application

Abstract

ABSTRACTWell-crystalline Sn-doped ZnO nanowires were grown on p -type silicon substrates by simple non-catalytic ther-mal evaporation process. The prepared nanowires were examined in terms of their morphological, composi-tional and structural properties which revealed that the as-grown nanowires are well-crystalline Sn-doped ZnO,possessing wurtzite hexagonal phase structure and grown in very high density over whole silicon substrate.Further, the as-grown n -Sn-doped ZnO nanowires were used to fabricate n -Sn-ZnO/ p -Si heterojunction diode.Temperature dependant electrical properties (294Ð353 K and 373Ð433 K) of the fabricated heterojunction diodewere studied in the forward and reverse bias conditions and presented in this paper. The currentÐvoltage char-acteristics at varying temperature of the heterojunction diode reveal that both the quality factor and Schottkybarrier height depend on temperature. However, the mean barrier height is estimated 1.2 eV in one attempt ofanalysis when a Gaussian distribution of low barrier heights is considered and found almost 1 eV in anotherattempt when the Richardson plot is linearized. Furthermore, effective barrier heights of 0.55Ð0.75 eV areextracted in the temperature range 294Ð433 K when Tung model is used. These correspond to barrier heightsof 0.93Ð0.35 eV extracted from C Ð V analysis in the same range of temperatures. Although the latter resultsfrom C Ð V analysis exhibit closer correlation with the Schottky barrier heights extracted from IÐ V analysis butthe discrepancy between them still exist.KEYWORDS: Sn-Doped ZnO Nanowires, Heterojunction Diodes, IÐ V Characteristics, Electrical Properties.