Vapor-phase Synthesis, Properties And Device Of Dopen Ⅱ-Ⅵ Semiconductor Nanomaterials

Quasi-one dimensional (1D) nanomaterials, including nano wires (rods), nanotubes, nanobelts, nanocables, heterojunction and superlatice nanowires, are ideal systems for investigating the dependence of electrical transport, optical properties, magnetic properties, and mechanical properties on size and dimensionality.â…¡-â…¥is one of the most important materials in 1D nanomaterials. Though the research of 1Dâ…¡-â…¥nanomaterials already has been got considerable progresses in controlling synthesis of 1D nanomaterials with desired morphologies, components, and structures, it still remains a significant challenge to study the property of 1D nanomaterials, especially in the dopen nanomaterials. Focusing on the research of the property of dopen semiconductor nanomaterials, we have done a series of work, and the main contents and conclusion can be summarized as following:1. Self-assemble growth, synthesis and characterization of In-doped ZnO nanowiresThe In-doped ZnO (IZO) nanowires has been synthesized by a thermal evaporation method. The morphology and microstructure of the IZO nanowires has been extensively investigated using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The products in general contain several kinds of nanowires. In the present work we will introduct the growth mechanism of fishbone and comb nanosturctures. We compare the difference in room temperature CL image and spcturm between the two nanostructures. Room temperature PL spctrum shows one violet emission peak centered at 385nm.2. In-doped ZnO nanowires field effect transistor (FET)FETs are widely used in advaced integrated circuits due to their high yield and capabillity to scale down. However, research on FETs based on nanomaterials is still in the initial stage and has been limited to a few materials. In the present work we will introduce the fabrication of FET devices from single In-doped ZnO nanowire, and demostrate the potential of In-doped ZnO nanowire in electronic applications. The electron mobility (μ) can be estimated about 9.2cm²/V.S at V_DS=1V. And then, carrier concentration is like wise calculated fromρ= 1/σ= 1/nqμ, is about 2.1×10⁸cm^-1.3. Synthesis and optical properties of Mn doped ZnS polycrystalline nanowiresMn doped ZnS polycrystalline nanowires with the structure of wurtzite were synthesized by a simple thermal evaporation process. The field emission scanning electron microscopy (FE-SEM) revealed that the products contained two different diameters nanowires which located in different temperature zone. The nanowires with the diameters about 50nm and several tens of micrometers in length are observed in relative low-temperature zone (870-920℃). And the nanorods with the diameters about 600nm and several tens of micrometers in length are observed in high-temperature zone (920-950℃). PL study shows a blue band and an orange band, which are due to the surface states and the transitions of Mn2+ (⁴T₁(⁴G)-⁶A₁(⁶S)), respectively. Comparing the photoluminescence spectrum in the two different temperature zones a new emission band at 702nm is observed. And the emission peaks of nanowires with the diameters about 50nm are red-shift comparing to the nanowires with the diameters about 600nm, which is due to the size-dependent crystal field effect.