Synthesis and characterization of phosphorus-doped ZnO and (Zn,Mg)O thin films via pulsed laser deposition

The transport and optical properties of phosphorus-doped (Zn,Mg)O thin films grown via pulsed laser deposition (PLD) are studied. The carrier type of as-deposited (Zn,Mg)O:P films converts from n-type to p-type with increasing oxygen partial pressure. All the films exhibit good crystallinity with c-axis orientation. This result indicates the importance of oxidation conditions in realizing p-type (Zn,Mg)O:P films. The as-deposited ZnO:P film properties show a strong dependence on the deposition ambient at different growth temperatures. The resistivity of the samples deposited in O₃/O₂ mixture is two orders of magnitude higher than the films grown in oxygen and O₂/Ar/H₂ mixture. The room-temperature photoluminescence (PL) of the as-deposited films has been shown that growing in the O₂/Ar/H₂ mixture ambient significantly increases the band edge emission while inhibiting the visible emission. The enhanced ultraviolet (UV) emission in the films grown in O₂/Ar/H₂ mixture may result from hydrogen passivation of the deep level emission centers. The annealed ZnO:P films are n-type with nonlinear dependence of resistivity on annealing temperature. The resistivity increases in the films with annealing at 800°C while decreasing with further increasing annealing temperature. Strong visible light emission is observed from the ZnO:P films annealed in oxygen.     

(Zn,Mg)TiO_3微波介质陶瓷性能的改善

采用固相反应法制备了(Zn,Mg)TiO3(ZMT)微波介质陶瓷,研究分别添加CaTiO3和BaLiBSi对ZMT陶瓷介电性能的影响。结果表明:CaTiO3和BaLiBSi均能调节ZMT陶瓷的温度系数τε值;BaLiBSi能有效降低ZMT陶瓷的烧结温度,抑制Zn2TiO4相的产生,提高所制陶瓷的微波介电性能。当添加质量分数10%的CaTiO3时,950℃烧结的(Zn1.06Mg0.12)TiO3陶瓷的τε值接近零:–6×10–6/℃。加入质量分数1.2%的BaLiBSi时,900℃烧结的(Zn1.13Mg0.048)Ti1.29O3陶瓷具有最佳的微波介电性能:εr≈24.8,Q.f=10 898 GHz,τε=17×10–6/℃。     

LMBE法生长Mg0.2Zn0.8O及MSM型紫外探测器的制备

采用激光分子束外延(LMBE)方法在蓝宝石(0001)面生长了高质量的Mg0.2Zn0.8O薄膜,并对薄膜在空气中900℃进行了1h的退火处理,然后采用剥离方法在薄膜表面制作了Al叉指电极,制备出MSM型Mg0.2Zn0.8O光电导紫外探测器.对响应时间的测试表明,探测器的上升时间仅为14.3ns,下降时间为6.5μs.     

(Nb,Mg,Al)多元掺杂对ZnO压敏材料电学性质的影响

研究了(Nb,Mg,Al)多元掺杂对ZnO压敏材料电学性能的影响。施主Nb离子的掺杂显著提高了压敏电阻的势垒高度,这与它能提供晶界势垒形成所必需的正电荷和负电荷直接相关。小半径离子Mg和Al易于处在ZnO的填隙位置,适量的掺杂也能提高晶界势垒高度,这与处在填隙位置的金属离子能提供正电荷和负电荷有关。而且填隙掺杂还能有效地改善陶瓷的致密度和均匀度,从而降低了ZnO压敏电阻漏电流、残压比和提高了非线性。(Nb,Mg,Al) 多元掺杂的ZnO压敏电阻的漏电流、残压比和非线性系数分别达到了 0.3 mA、V40kA/V1mA 2.5和a 110。     

Thin‐film Cu(In,Ga)(Se,S)2‐based solar cell with (Cd,Zn)S buffer layer and Zn1−xMgxO window layer

(Cd,Zn)S buffer layer and Zn_1−x Mg_x O window layer were investigated to replace the traditional CdS buffer layer and ZnO window layer in Cu(In,Ga)(Se,S)₂ (CIGSSe)‐based solar cell. (Cd,Zn)S with band‐gap energy (E _g) of approximately 2.6 eV was prepared by chemical bath deposition, and Zn_1−x Mg_x O films with different [Mg]/([Mg] + [Zn]) ratios, x , were deposited by radio frequency magnetron co‐sputtering of ZnO and MgO. The estimated optical E _g of Zn_1−x Mg_x O films is linearly enhanced from 3.3 eV for pure ZnO (x  = 0) to 4.1 eV for Zn_0.6Mg_0.4O (x  = 0.4). The quality of the Zn_1−x Mg_x O films, implied by Urbach energy, is severely deteriorated when x is above 0.211. Moreover, the temperature‐dependent current density‐voltage characteristics of the CIGSSe solar cells were conducted for the investigation of the heterointerface recombination mechanism. The external quantum efficiency of the CIGSSe solar cell with the (Cd,Zn)S buffer layer/Zn_1−x Mg_x O window layer is improved in the wavelength range of 320–520 nm. Therefore, a gain in short‐circuit current density up to about 5.7% was obtained, which is higher conversion efficiency of up to around 5.4% relative as compared with the solar cell with the traditional CdS buffer layer/ZnO window layer. The peak efficiency of 19.6% was demonstrated in CIGSSe solar cell with (Cd,Zn)S buffer layer and Zn_1−x Mg_x O window layer, where x is optimized at 0.211. Copyright © 2017 John Wiley & Sons, Ltd.     

Compositional engineering of chemical bath deposited (Zn,Cd)S buffer layers for electrodeposited CuIn(S,Se)2 and coevaporated Cu(In,Ga)Se2 solar cells

A comparative study of chemical bath deposition (CBD) of ZnS, CdS, and a mixture of (Cd,Zn)S buffer layers has been carried out on electrodeposited CuIn(S,Se)₂ (CISSe) and coevaporated Cu(In,Ga)Se₂ (CIGS) absorbers. For an optimal bath composition with the ratio of [Zn]/[Cd] = 25, efficiencies higher than those obtained with CdS and ZnS recipes, both on co‐evaporated CIGS and electrodeposited CISSe, have been obtained independent of the absorber used. In order to better understand the (Cd,Zn)S system and its impact on the increased efficiency of cells, predictions from the solubility diagrams of CdS and ZnS in aqueous medium were made. This analysis was completed by in situ growth studies with varying bath composition by quartz crystal microbalance (QCM). The morphology and composition of the films were studied using scanning electron microscopy (SEM) and X‐ray photoelectron spectra (XPS) techniques. Preliminary XPS studies showed that films are composed of a mixture of CdS and Zn(O,OH) phases and not a pure ternary Cd_{1 − x}Zn_xS compound. The effect of the [Zn]/[Cd] molar ratio on properties of the corresponding CISSe and CIGS solar cells was investigated by current voltage [J(V)] and capacitance voltage [C(V)] characterizations. The origin of optimal results is discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

NiO薄膜的脉冲激光沉积及其结构和光学特性研究

利用脉冲激光沉积法在ITO玻璃衬底上制备了NiO薄膜,利用XRD、AFM对样品的晶体结构和表面形貌进行了表征,并对其透射光谱进行了测试,研究了衬底温度及脉冲激光能量对所制NiO薄膜的结构、形貌和光学特性的影响。结果表明:在脉冲激光能量为180 mJ、衬底温度为600~700℃条件下所制备的样品为沿(111)晶面择优取向生长的多晶NiO薄膜,薄膜结晶质量良好,表面颗粒排列均匀,可见光透射率较高,禁带宽度为3.40~3.47 eV。     

Zn,Mg:LiNbO3晶体的光学特性研究

为了研制出结合Zn:LiNbO3与Mg:LiNbO3优点的晶体,采用提拉法从熔体中生长了Zn,Mg:LiNbO3晶体,并对它的配方和生长性能、光学均匀性、抗光折变以及倍频性能进行了研究,生长出了尺寸达40mm×70mm、双折射率梯度优于10-4/cm量级的Zn,Mg:LiNbO3晶体,倍频得到了20mJ的0.532μm的绿光输出,转换效率达到45%。该晶体是一种很有前途的非线性光学材料。     

钙钛矿型铌锌酸铅陶瓷材料合成及其性能

用Ｘ射线衍射和差热分析研究了铌锌酸铅Ｐｂ〔（Ｚｎ０．７Ｍｇ０．３）１／３Ｎｂ２／３〕Ｏ３陶瓷材料普通合成法和两种铌铁矿先驱体合成法的合成机理。研究表明，该材料的合成过程中，首先生成焦绿石相然后在较高温度生成钙钛矿相，先驱体法可以明显抑制焦绿石相的生成并使其反应温度向高温推迟，从而可以明显提高钙钛矿的产率。而简单先驱体法（ＰｂＯ＋ＺＮ＋ＭＮ）比复合先驱体法（ＰｂＯ＋ＺＭＮ）具有更好的合成效果。采用简单先驱体法通过合适的合成工艺可以制得钙钛矿含量大于９５％的Ｐｂ〔（Ｚｎ０．７Ｍｇ０．３）１／３Ｎｂ２／３〕Ｏ３陶瓷材料，其介电温谱具有明显的弥散性，为无序铁电陶瓷材料。研究发现，差热分析作为判断焦绿石和钙钛矿反应温度的重要依据，可以用于铌锌酸铅系陶瓷材料钙钛矿的合成研究。     

钛酸钙对BZN-CaTiO3系统介电性能的影响

研究了利用电子陶瓷工艺制得的主晶相为Ba(Zn1/3Nb2/3)O3(BZN)和CaTiO3的新型陶瓷,BZN具有立方钙钛矿结构。通过烧结温度的改变得到不同介电性能的陶瓷材料,发现CaTiO3的添加量对系统介电性能有显著影响。在1 395℃烧结的BZN-CaTiO3陶瓷,当CaTiO3的添加量为60%(质量分数)时介电性能最佳,其εr为99.97,tgδ为0.54×10-4,αC为–13.05×10-6℃–1(25~85℃,1MHz下测量)。     

Structure of chemically deposited Zn(S,O,OH) buffer layer and the effects on the performance of Cu(in,Ga)Se2 solar cell

The effects of the immersion into a NH₃ aqueous solution on the structural characteristics of the chemically deposited Zn(S,O,OH) layer and photovoltaic performance of the CIGS/Zn(S,O,OH) solar cells were investigated with structural and electrical characterizations. The as‐deposited‐Zn(S,O,OH) layer possessed a layered structure of upper Zn(OH)₂ and Zn(S,O) layers, and the upper Zn(OH)₂ layer was removed by the immersion. The conversion efficiency for the CIGS solar cell was improved from 6.8% to 13.7% by removing the upper Zn(OH)₂ layer during the immersion. Copyright © 2015 John Wiley & Sons, Ltd.     

The Zn(S,O,OH)/ZnMgO buffer in thin film Cu(In,Ga)(S,Se)2‐based solar cells part I: Fast chemical bath deposition of Zn(S,O,OH) buffer layers for industrial application on Co‐evaporated Cu(In,Ga)Se2 and electrodeposited CuIn(S,Se)2 solar cells

This paper is focused on the basic study and optimization of short time (<10 min) Chemical Bath Deposition (CBD) of Zn(S,O,OH) buffer layers in co‐evaporated Cu(In,Ga)Se₂ (CIGSe) and electrodeposited CuIn(S,Se)₂ ((ED)‐CIS) solar cells for industrial applications. First, the influence of the deposition temperature is studied from theoretical solution chemistry considerations by constructing solubility diagrams of ZnS, ZnO, and Zn(OH)₂ as a function of temperature. In order to reduce the deposition time under 10 min, experimental growth deposition studies are then carried out by the in situ quartz crystal microgravimetry (QCM) technique. An optimized process is performed and compared to the classical Zn(S,O,OH) deposition. The morphology and composition of Zn(S,O,OH) films are determined using SEM and XPS techniques. The optimized process is tested on electrodeposited‐CIS and co‐evaporated‐CIGSe absorbers and cells are completed with (Zn,Mg)O/ZnO:Al windows layers. Efficiencies similar or even better than CBD CdS/i‐ZnO reference buffer layers are obtained (15·7% for CIGSe and 8·1% for (ED)‐CIS). Copyright © 2009 John Wiley & Sons, Ltd.     

Zn_(1-x)Mg_xO薄膜的低压MOCVD生长与性质

利用低压金属有机物气相沉积 (L P- MOCVD)技术 ,采用两步生长法 ,在 (0 0 0 1 )蓝宝石衬底上获得了纤锌矿结构的 Zn1 - x Mgx O合金单晶薄膜 .实验发现随着 Mg原子的增多 ,Zn Mg O的晶格常数逐渐减小 .X射线衍射谱中未出现除 (0 0 0 2 )峰之外的其他峰位 ,表明该合金薄膜具有很强的择优取向和较好的晶体质量 .室温透射谱与光致发光谱显示 ,其吸收边或带边发光峰随 Mg原子浓度的增加首先出现红移然后出现蓝移 .该反常现象与 Zn Mg O薄膜中产生的杂质缺陷的行为有关 .研究表明在 MOCVD生长 Zn Mg O合金薄膜过程中 ,必须优化与控制反应条件 ,以抑制杂质缺     

Junction formation by Zn(O,S) sputtering yields CIGSe‐based cells with efficiencies exceeding 18%

In an effort to reduce the complexity and associated production costs of Cu(In,Ga)Se₂ (CIGSe)‐based solar cells, the commonly used sputtered undoped ZnO layer has been modified to eliminate the requirement for a dedicated buffer layer. After replacing the ZnO target with a mixed ZnO/ZnS target, efficient solar cells could be prepared by sputtering directly onto the as‐grown CIGSe surface. This approach has now been tested with high‐quality lab‐scale glass/Mo/CIGSe substrates. An efficiency of 18.3% has been independently confirmed without any post‐deposition annealing or light soaking. Copyright © 2013 John Wiley & Sons, Ltd.     

Zn_(0.7)Co_(0.3)(Ti_(1-x)Sn_x)Nb_2O_8陶瓷微波介电性能研究

采用传统固相法制备Zn0.7Co0.3(Ti1-xSnx)Nb2O8(x=0.1,0.15,0.2,0.25,0.3,0.35)微波陶瓷。研究了Sn取代Ti对Zn0.7Co0.3(Ti1-xSnx)Nb2O8微波介质陶瓷的物相结构与介电性能的影响。XRD研究表明,Zn0.7Co0.3(Ti1-xSnx)Nb2O8陶瓷主晶相为ZnTiNb2O8,有极少杂相Zn0.17Ti0.5Nb0.33O2存在;随着Sn含量的增加,陶瓷晶格常数增大,晶胞体积变大,陶瓷密度增大;电子扫描显微镜(SEM)显示随着Sn含量增加陶瓷结构致密;相对介电常数εr逐渐变小,温度系数τf逐渐变小,Q×f值逐渐增大;当Sn含量为0.35时,烧结温度为1 080℃,εr=30.5,Q×f=46 973GHz,τf=-45.4×10-6/℃。     

PbO-B2O3-CuV2O6掺杂对(Pb,Ca,La)(Fe,Nb)O3陶瓷微波介电性能的影响

研究了PbO3-CuV2O6(PBC)玻璃对(Pb,Ca,La)(Fe,Nb)O3(PCLFN)陶瓷微波介电性能的影响.当纯PCLFN陶瓷在1150℃烧结,介电常数εr=103,品质因数与频率之积Qf=5640 GHz,频率温度系数τf=7.1×10-6/℃.PBC玻璃添加剂能降低PCLFN陶瓷的烧结温度到1 050℃左右,同时能保持良好的介电性能.随着PBC玻璃添加量的质量分数从1.0%增加2.0%,陶瓷的Qf值减小.掺杂ω(PBC)=1%玻璃、在1 050℃烧结的陶瓷样品,能获得良好的微波介电性能为Qf=5 392 GHz,τf=8.18×10-6/℃,εr=101.     

Magnetic and magnetotransport properties in the n-type (Ga,Mn)N thin films

We present the magnetic and magnetotransport properties of epitaxial (Ga,Mn)N films with nominal Mn concentration (x=0.1–0.73%) grown by plasma-enhanced molecular beam epitaxy (PEMBE). X-ray diffraction (XRD) reveals that (Ga,Mn)N has the single-phase wurtzite structure without secondary phases. The epitaxial (Ga,Mn)N films were found to exhibit n-type conductivity, ferromagnetic ordering with Curie temperature in the range 550–700 K, and in-plane magnetic anisotropy. The negative magnetoresistance (MR) was observed at temperatures below 50 K and was found to gradually increase with decreasing temperature.     

BaTiO3陶瓷中Nb2O5-Zn0.8Mg0.2TiO3的掺杂效应

研究了BaTiO3-Nb2O5-Zn0.8Mg0.2TiO3系统的介电性能及微观性能。SEM和XRD分析发现,在掺杂x(Nb)=1%的BaTiO3陶瓷中,Zn0.8Mg0.2TiO3的固溶度小于4%。Nb2O5和Zn0.8Mg0.2TiO3用量均为1%时,BaTiO3陶瓷为赝立方相结构,当x(Nb)>2%时,陶瓷样品(002)和(200)衍射峰相互分开,研究表明,BaTiO3陶瓷为四方相,且随着Nb用量增加,四方率增强。此外,Nb用量增加还使BaTiO3陶瓷室温介电常数降低,而同时居里点升高。当x(Nb)=2%和x(ZMT)=1%时,在空气中于1 180℃下烧成的BaTiO3陶瓷材料的主要性能指标为:298 K时介电常数2ε98 K=2 004,介电损耗tanδ=0.84%,密度ρ=1.4×1012Ω.cm,-55~ 150℃,电容量温度变化率△C/C≤±15%。     

MgxNi1-xMn2O4薄膜结构与电学特性研究

采用化学溶液沉积法在Al_2O_3衬底上生长了Mg_xNi_(1-x)Mn_2O_4(MNM,x=0,0.05,0.10,0.15,0.20)薄膜.通过X射线衍射仪和场发射扫描电子显微镜研究了Mg掺杂浓度对MNM薄膜的结构特性的影响,MNM薄膜均匀致密,具有良好的结晶性,为单一立方尖晶石结构.变温电流-电压特性研究显示,MNM薄膜的电输运特性符合小极化子变程跳跃电导模型,同时获得了不同Mg掺杂浓度的MNM薄膜的电阻率ρ、特征温度T_0和电阻温度系数α.研究结果表明,Mg的掺杂对MNM薄膜的结构和电学特性都有一定的影响.     

Zn缺位对Ba(Co_(0.6)Zn_(0.4))_(1/3)Nb_(2/3)O_3陶瓷性能的影响

采用传统固相反应法制备了Ba(Co0.58Y0.02Zn0.4-x)1/3Nb2/3O3(x=0,0.01,0.02,0.03,0.04,0.06)陶瓷,系统研究了Zn缺位对陶瓷的物相组成、微观结构和微波介电性能的影响。X线衍射(XRD)结果表明所有配方陶瓷的主晶相均为BaZn0.33Nb0.67O3-Ba3CoNb2O9(BCZN),并存在不同量的第二相Ba8CoNb6O24,适量的Zn缺位可提高BCZN体系的有序度,x=0.02时,其有序度最大。电镜扫描(SEM)结果表明适量的Zn缺位可促进烧结致密化,但Zn缺位过多,会使第二相增多,陶瓷的致密度恶化。随着x的增加,陶瓷的介电常数(εr)基本不变,但品质因数与频率的乘积(Q×f)得到了有效的改善,谐振频率温度系数(τf)先减小后增大。当x=0.02时,BCZN体系陶瓷的εr=35.12,Q×f=52 678GHz,τf=3.28×10-6/℃。