HgCdTe MIS器件制备及其C-V特性研究

通过在P-HgCdTe上生长阳极硫化膜和ZnS介质钝化层,制备出了性能较好的MIS器件,并通过对MIS器件C-V特性的分析,获得了ZnS/自身钝化膜/P-HgCdTe的界面特性.所测的界面电荷密度在1010～1011cm-2之间,平带电压在2 V以下.     

射频磁控溅射法在柔性聚酰亚胺衬底上制备ZnS薄膜及其特性研究

为使Ⅱ-Ⅵ族化合物ZnS薄膜具有可弯曲性,选用柔性的聚酰亚胺作为衬底材料,用射频磁控溅射法沉积ZnS薄膜,对所制备薄膜的结晶结构、组分和光学特性进行分析.实验结果表明,所制备薄膜为结晶态的闪锌矿ZnS结构,择优取向为(111)晶面,晶粒尺寸为25.6 nm.薄膜组分接近化学计量比,并具有少量的S损失.薄膜在可见光区和近红外光区的平均透射率分别为82.0％和90.5％,透光特性良好.作为对比,在钠钙玻璃衬底上溅射的ZnS薄膜的结晶度高于聚酰亚胺衬底薄膜,但其透射率略低于柔性ZnS薄膜.实验结果表明了用磁控溅射法在柔性聚酰亚胺衬底上制备ZnS薄膜的可行性.     

Atomistic tight-binding computations of the electronic properties of ZnSe/ZnS core/shell nanocrystals under applied electric field

The effect of applied electric field on the electronic properties of spherical ZnSe/ZnS core/shell nanocrystals of experimentally relevant size is investigated by the atomistic tight-binding theory. Using this model, the calculations show that a range of electronic properties, including the single-particle spectra, atomistic characters, charge densities, excitonic energies, ground-state coulomb energies, overlaps of the electron and hole wave functions and oscillation strengths, all depend on the strengths of the applied electric field. The spatial distributions of the electron and hole wave functions are induced by the applied electric field. The analysis demonstrates a clear manipulation of the electronic properties of ZnSe/ZnS core/shell nanocrystals by introducing and varying the applied electric field strengths. According to the comprehensive investigations, I suppose that these atomistic computations will be of prospective help for experimental works concentrated on the new optoelectronic devices based on the applied electric field.     

The pure rotational spectrum of ZnS (XΣ)

The pure rotational spectrum of ZnS (X¹Σ⁺) has been measured using direct-absorption millimeter/sub-millimeter techniques in the frequency range 372-471 GHz. This study is the first spectroscopic investigation of this molecule. Spectra originating in four zinc isotopologues (⁶⁴ZnS, ⁶⁶ZnS, ⁶⁸ZnS, and ⁶⁷ZnS) were recorded in natural abundance in the ground vibrational state, and data from the v = 1 state were also measured for the two most abundant zinc species. Spectroscopic constants have been subsequently determined, and equilibrium parameters have been estimated. The equilibrium bond length was calculated to be r_e ∼ 2.0464 Å, which agrees well with theoretical predictions. In contrast, the dissociation energy of D_E ∼ 3.12 eV calculated for ZnS, assuming a Morse potential, was significantly higher than past experimental and theoretical estimates, suggesting diabatic interaction with other potentials that lower the effective dissociation energy. Although ZnS is isovalent with ZnO, there appear to be subtle differences in bonding between the two species, as suggested by their respective force constants and bond length trends in the 3d series.     

Characterization and optical properties of ZnS nanorods branched out from ZnS film on Zn foil

Complex nanomaterial‐film‐metal substrate architectures, which are composed of ZnS nanorods, island‐like ZnS film and Zn foil, have been formed via a simple vapor deposition route. The growth of the complex nanostructures is initiated by the preferred formation of ZnS film, and ZnS nanorods branches out from ZnS film flows a liquid‐phase epitaxial growth mode. The ZnS nanorod is switched to an angle, which may be attributed to the sudden change of vapor pressure and temperature reduction by the end of vapor deposition process. The room‐temperature photoluminescence spectrum shows that complex ZnS nanostructures have a strong blue emission band centered at about 423 nm and a weak broad green emission band centered at about 515 nm. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Interaction behavior study of HCl on (ZnS)n (n = 1–12) clusters and HCl effect on Hg0 adsorption

The interaction behavior of HCl and (ZnS)_n (n = 1–12) clusters and HCl effect on Hg⁰ adsorbed by (ZnS)_n have been studied theoretically. The combined genetic algorithm and density functional theory (GA-DFT) method has been used to obtain the structures of (ZnS)_nHCl and (ZnS)_nHgHCl (n = 1–12) clusters. The structural properties of (ZnS)_nHCl and (ZnS)_nHgHCl have been analyzed. The adsorption energies and interaction energies have been calculated. Bond length and bond order analysis has revealed that S H and Zn Cl bonds form after HCl adsorbed on (ZnS)_n clusters, while Hg⁰ can only weakly bind with (ZnS)_nHCl clusters. According to thermodynamic adsorption analysis, the formation of (ZnS)_nHCl clusters from (ZnS)_n and HCl are spontaneous because of their negative Gibbs free energy changes. The formation of (ZnS)_nHgHCl from (ZnS)_nHCl and Hg are nonspontaneous for n = 1–4 and 9, and the Gibbs free energy changes have small negative values for other sizes. Electron localization function and noncovalent interaction (NCI) analysis of (ZnS)₁₀HgHCl manifest that Hg and its nearest Zn form zinc amalgam. Projected density of state study has been performed to obtain the interaction nature of HCl and (ZnS)_n clusters and Hg⁰ adsorption on (ZnS)_nHCl clusters. Based on our study, HCl is chemical adsorbed by (ZnS)_n clusters except (ZnS)₄ cluster. After (ZnS)_n adsorbs HCl, Hg⁰ can physically adsorb on (ZnS)_nHCl clusters. The strength of Hg⁰ on (ZnS)_nHCl is comparable to that of Hg⁰ on (ZnS)_n, indicating that HCl can hardly affect the adsorption of Hg⁰ on ZnS clusters.     

ZnS微球的制备及吸光性能研究

采用溶剂热法,以醋酸锌和硫脲为原料,去离子水和无水乙醇的混合溶液为反应介质制备了ZnS微球。利用XRD、SEM、UV-Vis吸收光谱探讨了反应温度和时间对产物晶型、颗粒形貌以及吸光性能的影响。结果表明:ZnS微球的晶型和形貌对反应温度比较敏感,反应时间对晶体的结晶度和吸光率影响较大。采用溶剂热法的最佳合成温度为150℃左右,反应时间为12 h;该条件下生成的ZnS微球物相较为纯净、结晶完全,且分散性良好,带隙约为3.3 eV。     

Improvement of the cell performance in the ZnS/Cu(In,Ga)Se2 solar cells by the sputter deposition of a bilayer ZnO : Al film

ZnS is a candidate to replace CdS as the buffer layer in Cu(In,Ga)Se₂ (CIGS) solar cells for Cd‐free commercial product. However, the resistance of ZnS is too large, and the photoconductivity is too small. Therefore, the thickness of the ZnS should be as thin as possible. However, a CIGS solar cell with a very thin ZnS buffer layer is vulnerable to the sputtering power of the ZnO : Al window layer deposition because of plasma damage. To improve the efficiency of CIGS solar cells with a chemical‐bath‐deposited ZnS buffer layer, the effect of the plasma damage by the sputter deposition of the ZnO : Al window layer should be understood. We have found that the efficiency of a CIGS solar cell consistently decreases with an increase in the sputtering power for the ZnO : Al window layer deposition onto the ZnS buffer layer because of plasma damage. To protect the ZnS/CIGS interface, a bilayer ZnO : Al film was developed. It consists of a 50‐nm‐thick ZnO : Al plasma protection layer deposited at a sputtering power of 50 W and a 100‐nm‐thick ZnO : Al conducting layer deposited at a sputtering power of 200 W. The introduction of a 50‐nm‐thick ZnO : Al layer deposited at 50 W prevented plasma damage by sputtering, resulting in a high open‐circuit voltage, a large fill factor, and shunt resistance. The ZnS/CIGS solar cell with the bilayer ZnO : Al film yielded a cell efficiency of 14.68%. Therefore, the application of bilayer ZnO : Al film to the window layer is suitable for CIGS solar cells with a ZnS buffer layer. Copyright © 2012 John Wiley & Sons, Ltd.     

一维ZnE(E=S,Se)网状微米晶须的化学气相合成及生长机理研究

以Zn粉为原料,在CuE(E=S, Se)微米球的辅助下,采用化学气相沉积(CVD)法在Si衬底上成功制备出微米级ZnE(E=S, Se)网状晶须.用XRD,EDS,SEM和PL谱分别对产物的结构、成分、形貌和结晶质量进行了测试和分析.结果表明:生长的ZnS和ZnSe微米晶须均为立方闪锌矿结构,长度达300 μm以上,具有接近理想化学计量比的成分和较高的结晶质量.ZnE微米晶须的生长符合氧化还原反应下的气-液-固生长机制,Cu3Zn合金充当了实际的微米晶须生长催化剂,在晶须生长过程中Cu3Zn合金汇聚在一起使ZnE微米晶须形成交叉网状结构.