J. Phys. Chem. B 2006, 110, 25869-25874
25869
Novel Zn1-xMnxSe (x ) 0.1-0.4) One-Dimensional Nanostructures: Nanowires, Zigzagged Nanobelts, and Toothed Nanosaws Jin Young Lee, Dae Sung Kim, Ja Hee Kang, Sang Won Yoon, Hyunju Lee, and Jeunghee Park* Department of Chemistry, Korea UniVersity, Jochiwon 339-700, Korea ReceiVed: September 4, 2006; In Final Form: October 15, 2006
Novel Zn1-xMnxSe one-dimensional nanostructuressstraight nanowires (x ) 0.1 and 0.3), zigzagged nanobelts (x ) 0.4), and toothed nanosaws (x ) 0.4)swere synthesized using the chemical vapor deposition method. They all consisted of single-crystalline wurtzite ZnSe crystals, irrespective of the Mn content. In particular, the nanosaws have a unique structure in which double-sided teeth are rooted in the nanowire core and bent so as to align as two parallel rows. The long axis is parallel to the [011h0] direction, and all of the teeth have the [0001] growth direction. The X-ray diffraction pattern confirms the formation of wurtzite ZnSe crystal and the decrease of the lattice constant owing to Mn doping. The Mn2+ emission at 2.1 eV (appeared below 100 K), originating from the d-d (4T1 f 6A1) transition, proves the effective substitution of Mn2+ ions at the tetrahedral coordinate sites.
1. Introduction Currently, a tremendous amount of research activity is under way into the use of one-dimensional (1D) nanostructures (e.g., nanotubes, nanorods, nanowires, nanobelts) as well-defined building blocks for the fabrication of various nanoscale devices.1 Semiconductor 1D nanostructures containing paramagnetic ions are drawing considerable attention for possible application in spintronics and quantum interference information processing. They belong to the family of diluted magnetic semiconductors (DMSs), in which the sp-d exchange interaction between the semiconductor and the paramagnetic ions induces unique magnetic and optomagnetic properties.2,3 In particular, the 1D nanostructures of Mn-doped III-V, II-VI, and IV-VI semiconductors, e.g., GaN,4-9 GaP,10 ZnO,11-16 ZnS,6,17-22 CdS,6,23-25 and PbSe,26 have been synthesized by various methods, and their optical/magnetic properties have also been investigated. Zinc selenide (ZnSe) is a wide band gap semiconductor material (its band gap energy, Eg, is 2.7 eV at room temperature) having potential in short wavelength optoelectronic devices.27-31 A tremendous amount of research has been carried out into ZnSe nanorods, nanowires, nanorings, and nanocables.32-41 However, the synthesis of Mn-doped ZnSe 1D nanostructures has rarely been reported and thus still remains a significant challenge. Herein, we report the successful synthesis of single-crystalline Mn-incorporated ZnSe (Zn1-xMnxSe) 1D nanostructures, with various Mn contents (x ) 0, 0.1, 0.3, and 0.4) and morphologies, using the chemical vapor deposition method. For x ) 0.1 and 0.3, the ZnSe 1D nanostructures are grown with a perfect nanowire form. As the Mn content reaches x ) 0.4, however, they adopt unique morphologies for 1D nanostructures, such as zigzagged nanobelts and toothed nanosaws. In contrast, the Mn-doped ZnSe nanoparticles usually contain a lower concentration of Mn, which is
