LPCVD法在制绒单晶硅片衬底上制备ZnO∶B透明导电薄膜及其性能的研究

采用低压化学气相沉积法(LPCVD)在制绒的单晶硅片衬底上制备了B掺杂ZnO(BZO)的透明导电薄膜,研究了B2H6掺杂量、沉积时间对BZO薄膜的微观形貌、导电性能及光学减反性能的影响.结果表明,在制绒单晶硅片衬底上制备的BZO薄膜均呈现“类金字塔”的绒面结构,其平均晶粒尺寸在200 ～ 500 nm之间,并随B2H6掺杂量增加而减小;BZO薄膜的方阻随沉积时间的增加而呈线性迅速减小的趋势,当沉积时间为420 s时,BZO薄膜的方块电阻低至28 Ω/□;在制绒单晶硅片上制备BZO薄膜后,表面平均反射率由15;明显降低至5;左右,表现出优异的光学减反性能.     

超声喷雾热解法制备不同掺杂浓度ZnO∶Eu薄膜

以醋酸锌,氯化铕的混合水溶液为前驱体,采用超声喷雾热解法在ITO导电玻璃衬底上制备了掺杂不同Eu浓度的ZnO∶Eu薄膜。通过扫描电镜(SEM),X射线衍射(XRD)和光致发光(PL)谱对ZnO∶Eu薄膜的形貌,结构和光学性质进行了研究。通过对比掺杂不同Eu浓度的ZnO∶Eu薄膜的结构和光学性能,可知在掺杂浓度为6mol%时薄膜的性能最好。SEM照片表明制备的ZnO∶Eu薄膜为致密的纳米颗粒薄膜,ZnO∶Eu晶粒尺寸大约在200～250 nm。XRD图谱表明当掺杂浓度为6mol%时,ZnO∶Eu薄膜具有很好的六角纤锌矿结构,且在2θ=50.47°处出现Eu2O3的衍射峰。激发光谱测试表明ZnO∶Eu薄膜在280 nm,373 nm,393 nm处有较强的紫外吸收。当用280 nm激发光激发时ZnO∶Eu薄膜在613 nm处具有较强的红光发射。     

薄膜厚度对MOCVD法沉积ZnO透明导电薄膜的影响

本文研究了薄膜厚度对MOCVD技术制备未掺杂ZnO薄膜的微观结构和电学特性影响.XRD和SEM的研究结果表明,随着薄膜厚度的增加,ZnO薄膜(110)峰趋于择优取向,且晶粒逐渐长大,薄膜从球状和细长棒状演变为具有类金字塔绒面结构特征的ZnO薄膜;Hall测量表明,较厚的ZnO薄膜有助于提高薄膜电学特性,可归于晶粒长大和晶体质量提高.40min沉积时间(膜厚为1250nm)制备出的ZnO薄膜具有明显绒面结构,其晶粒尺寸为300～500nm,电阻率为7.9×10-3Ω·cm,迁移率为26.8cm2/Vs.     

Nb掺杂ZnO透明导电薄膜的结构以及光电性能研究

采用直流磁控溅射法在玻璃衬底上制备了高质量的Nb掺杂ZnO( NZO)透明导电薄膜.为了研究薄膜厚度对薄膜性质的影响,制备了五个厚度分别为239 nm,355 nm,489 nm,575 nm和679 nm的样品.XRD结果表明,ZnO∶ Nb薄膜是具有六角纤锌矿结构的多晶薄膜,并且具有垂直于衬底的c轴择优取向.随着膜厚的增加,薄膜的结晶质量明显提高.当厚度从239 nm增加到489 nm时,平均晶粒尺寸从19.7 nm增加到24.7 nm,薄膜的电阻率持续减小;当厚度进一步增加时,晶粒尺寸略有减小,电阻率有所增加.本实验获得的最低电阻率为4.896×10-4Ω·cm.随膜厚的增加,光学带隙先增大后减小.所有薄膜在可见光区域的平均透过率均超过88.3;.     

镓掺杂氧化锌透明导电薄膜的制备及其性能研究

采用射频磁控溅射方法在玻璃基片上制备了镓掺杂氧化锌(Ga∶ ZnO)透明导电薄膜,通过XRD、XPS、四探针仪和分光光度计等表征技术,研究了衬底温度对Ga∶ ZnO薄膜结构、组分、光学和电学性质的影响.结果表明:所有样品均为具有(002)择优取向的高质量透明导电薄膜,其晶体结构和光电性能与衬底温度密切相关.当衬底温度为673 K时,所制备的Ga∶ ZnO薄膜具有最大的晶粒尺寸(72.6 nm)、最低的电阻率(1.3×10-3Ω·cm)、较高的可见∶ZnO薄膜的光学能隙,结果显示随着衬底温度的升高,薄膜的光学能隙单调增加.     

退火气氛和镧掺杂浓度对ZnO薄膜结构和光学性能的影响

采用溶胶-凝胶浸渍提拉法在玻璃衬底上制备Zn1-xLaxO(x=0～0.04)(LZO)薄膜,分别在空气、氮气和氩气条件下进行退火,探讨了不同退火气氛和不同镧掺杂浓度对其结构和光学性能的影响.XRD和SEM结果表明:氩气退火条件下ZnO的晶粒尺寸比空气退火条件下和氮气退火条件下的晶粒尺寸略小,且ZnO晶粒的尺寸随着镧掺杂浓度的增加而减小.薄膜光致发光(PL)测量表明:紫光发光带中心在氩气下退火相对于空气下退火存在略微的蓝移,而在氮气下退火则相反;ZnO紫光发光带的位置随着镧掺杂浓度的增加先红移而后蓝移.禁带宽度在镧掺杂量为2;时达到最小值,说明镧可以有效地调节ZnO的禁带宽度.     

B掺杂量对LPCVD生长大面积ZnO透明导电薄膜性能的影响

采用低压化学气相沉积(LPCVD)技术在大面积的玻璃衬底上制备了B掺杂ZnO(BZO)透明导电薄膜,研究了不同B2H6掺杂量对BZO薄膜微观形貌、导电能力及其均匀性、透光率等性能的影响.结果表明,所制备的BZO薄膜表面具有自生长的绒面结构;B2H6掺杂量由30 sccm增加到60 sccm,BZO薄膜的方阻由28.6Ω/□减小到14.1 Ω/□,导电能力显著增强,同时方阻均匀性也明显提升;BZO薄膜在长波区的透光率随B2H6掺杂量的增加而明显降低,综合透光率结果,最佳B2H6掺杂量控制在60～ 90 sccm之间.     

Fe、Ni共掺杂ZnO薄膜的溶胶-凝胶法制备及性能研究

采用溶胶-凝胶法在玻璃基片上旋涂生长了ZnO、Fe, Ni单掺杂及(Fe,Ni)共掺杂ZnO薄膜.产物的显微照片及XRD图谱结果表明, 该方法所制备的ZnO薄膜表面均匀致密,都存在(002)择优取向,具有六角纤锌矿结构,晶粒尺寸平均在13 nm 左右,振动样品磁强计(VSM)测试结果显示掺杂ZnO薄膜均存在室温铁磁性.光致发光(PL)测量表明所有样品薄膜的PL谱主要由较强的紫外发光峰(394 nm)、蓝光峰(420 nm)、绿光峰(480 nm)组成.Fe、Ni单掺杂和共掺杂并不改变ZnO薄膜的发光峰位置,但掺杂后该紫外发光峰减弱,420 nm处的蓝光峰增强.     

La掺杂对ZnO纳米薄膜微观结构与光学特性的影响

采用射频磁控溅射方法在Si衬底上制备了不同掺杂量的La掺杂ZnO(ZnO∶La)薄膜.用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见分光光度计和光致荧光发光(PL)等表征技术,研究了不同掺杂量对ZnO∶ La薄膜的微观结构和光学特性的影响.结果表明,所有薄膜均只出现的(002)衍射峰,表明La3+可以替代ZB2或者进入ZnO晶格间隙,并未改变ZnO的六角纤锌矿结构.通过计算可知La掺杂可以抑制ZnO的晶粒增长.可见光范围的透过率超过80;,同时随着La掺杂量的增加,薄膜的光学带隙值逐渐增大.通过对光致发光谱的研究表明,La掺杂可以增强ZnO薄膜室温下的紫外光发光强度.     

磁控溅射技术室温生长氢化ZnO∶Ga薄膜及其特性研究

采用直流脉冲磁控溅射方法,在室温下生长氢化Ga掺杂ZnO薄膜(GZO/H),并通过湿法后腐蚀技术获得绒面结构.研究了室温下H2流量对薄膜结构、光电性能及表面形貌的影响.实验表明,氢化GZO(GZO/H)薄膜具有良好的(002)晶面择优取向生长,引入适当流量的H2可以有效提高薄膜的电学特性,GZO/H薄膜具有更低的电阻率以及较高的迁移率和载流子浓度.当通入H2流量为6 sccm时,薄膜电阻率为6.8 ×10-4 Ω·cm,Hall迁移率达34.2 cm2/Ⅴ·s,制备的GZO/H薄膜可见光区域平均透过率优于85;.此外,研究了H2流量对湿法腐蚀后绒面GZO/H薄膜表面形貌的影响,提出了一种薄膜绒面结构形成过程模型.     

反应磁控溅射制备AZO薄膜相结构的演化及机理研究

在室温下,利用直流反应磁控溅射技术在不同的氧气流量下沉积ZnO∶ Al (AZO)薄膜.采用XRD、SEM和TEM技术分析薄膜相成分、表面截面形貌及微观结构.结果表明:氧气流量为2.5 sccm时,沉积形成的薄膜为不透明具有金属导电性能的AZO/Zn( AZO)双层复合膜结构;氧气流量为3.5 sccm时,沉积形成了透明导电的AZO薄膜;氧气流量为5.0 sccm时,形成了透明不导电且含有纳米Al2O3颗粒的AZO薄膜;此外,AZO薄膜在400℃退火后,薄膜晶粒长大和(002)晶面方向择优生长更加明显以及高氧气流量沉积的AZO薄膜中的纳米Al2O3颗粒消失.     

氨水浓度对化学浴沉积的Zn(O,S)薄膜形貌、结构和性能的影响

采用化学浴法,以ZnSO4·7H2O和SC( NH2)2作为反应前驱物,C6H5O7 Na3·2H2O作为络合剂,NH3·H2O 作为辅助络合剂和缓冲剂制备Zn(O,S)薄膜.采用SEM、EDS、XPS、XRD和透射光谱分析方法,研究氨水浓度对化学浴法制备的Zn(O,S)薄膜形貌、成分、结构和光学性能的影响以及Zn(O,S)薄膜的形成机理.结果表明:Zn(O,S)薄膜是由ZnO和ZnS纳米颗粒混合组成的,ZnO具有纤锌矿结构,ZnS是以非晶相存在.随着反应溶液中氨水浓度的降低,薄膜中所包含的ZnO逐渐减少,ZnS逐渐增加,S/Zn原子比逐渐增加,透射率和光学带隙也逐渐增大.     

加氮对直流电弧等离子体喷射金刚石膜生长、形貌和质量的影响

利用直流等离子体喷射化学气相沉积法制备掺氮的金刚石厚膜.本文研究了在甲烷/氩气/氢气中加入氮气对金刚石膜生长、形貌和质量的影响.反应气体的比例由质量流量计控制,在固定氢气(5000sccm)、氩气(3000sccm)、甲烷(100sccm)流量的情况下改变氮气的流量,即反应气体中氮原子和碳原子的变化比例(N/ C比)范围是从0.06到0.68.同时金刚石膜在固定的腔体压力(4kPa)和衬底温度(800℃)下生长.金刚石膜用扫描电镜(SEM)、拉曼谱和X射线衍射表征.结果表明,氮气在反应气体中的大量加入对直流等离子体喷射制备金刚石膜的形貌、生长速率、晶体取向、成核密度等有非常显著的影响.     

Plasma enhanced chemical vapor deposition of ZnO thin films

Zinc oxide thin films were deposited on silicon and corning-7059 glass substrates by plasma enhanced chemical vapor deposition at different substrate temperatures ranging from 36 to 400 °C and with different gas flow rates. Diethylzinc as the source precursor, H₂O as oxidizer and argon as carrier gas were used for the preparation of ZnO films. Structural and optical properties of these films were investigated using X-ray diffraction, reflection high energy electron diffraction, atomic force microscopy and photoluminescence. Highly oriented films with (0 0 2) preferred planes were obtained on silicon kept at 300 °C with 50 ml/min flow rate of diethylzinc without any post annealing. Reflection high energy electron diffraction pattern also showed the crystalline nature of these films. A textured surface with rms roughness ∼28 nm was observed by atomic force microscopy for the films deposited at 300 °C. A sharp peak at 380 nm in the PL spectra indicated the UV band-edge emission.     

射频磁控溅射生长ZnO薄膜及性能研究

采用射频磁控溅射技术在玻璃衬底生长ZnO及ZnO∶ Al薄膜,通过改变氩氧比、衬底温度和溅射功率获得样品.用X射线衍射仪、紫外-可见分光光度计、扫描电子显微镜进行表征.结果发现:室温下40W的溅射功率1h的溅射时间,改变氩氧比获得样品.XRD图谱中无明显衍射峰出现;紫外可见光分光光度计测试结果显示400nm波长以下,透光率在90;以上.说明薄膜生长呈无定形.衬底温度高于200℃样品,XRD有明显(002)衍射峰出现,在400～ 800 nm波长范围,透光率在88;以上,衬底温度300℃时,XRD衍射峰半高宽最小,晶粒尺寸大.TEM显示:衬底300℃晶粒尺寸最大,晶体发育好.在200℃掺铝ZnO薄膜,(002)峰不明显,有(101)峰出现.     

Hydrogenated amorphous silicon with substrate-dependent structure

Hydrogenated amorphous silicon (a-Si:H) thin films grown at 250°C on (1 0 0) crystalline substrate using plasma-enhanced chemical vapor deposition (PECVD) with SiH₄/H₂ gas flow ratio equal to 5/1 (sccm) are investigated by transmission electron microscopy. It is found that the thin film is totally amorphous when grown on a glass substrate. But when the substrate is changed to crystalline silicon, some crystalline grains are found embedded in the amorphous structure in certain regions even if the thickness of the film reaches 600 nm. It is suggested that the amorphous silicon film grown on a crystalline silicon substrate at a temperature of 250°C without heavy H₂ dilution is a mixed network of a small amount of crystalline silicon and the major portion of amorphous silicon.     

Homoepitaxial growth of 6H–SiC thin films by metal-organic chemical vapor deposition using bis-trimethylsilylmethane precursor

Homoepitaxial silicon carbide (SiC) films were grown on 3.5° off-oriented (0 0 0 1) 6H–SiC by metal-organic chemical vapor deposition (MOCVD) using bis-trimethylsilylmethane (BTMSM, C₇H₂₀Si₂). A pronounced effect of the growth conditions such as source flow rate and growth temperature on the polytype formation and structural imperfection of the epilayer was observed. The growth behavior was explained by a step controlled epitaxy model. It was demonstrated by high-resolution X-ray diffractometry and transmission electron microscopy that high-quality 6H–SiC thin films were successfully grown at the optimized growth condition of substrate temperature 1440°C with the carrier gas flow rate of 10 sccm.     

Effect of NH3 on the growth characterization of TiN films at low temperature

Titanium nitride (TiN) films were obtained by the atmospheric pressure chemical vapor deposition method of the TiCl₄–N₂–H₂ system with various flow rates of NH₃ at 600°C. The growth characteristics, morphology and microstructure of the TiN films deposited were analyzed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Without NH₃ addition, no TiN was deposited at 600°C as shown in the X-ray diffraction curve. However, by adding NH₃ into the TiCl₄–N₂–H₂ system, the crystalline TiN was obtained. The growth rate of TiN films increased with the increase of the NH₃ flow rate. The lattice constant of TiN films decreased with the increase of the NH₃ flow rate. At a low NH₃ flow rate, the TiN (2 2 0) with the highest texture coefficient was found. At a high NH₃ flow rate, the texture coefficient of TiN (2 0 0) increased with the increase of the NH₃ flow rate. In morphology observation, thicker plate-like TiN was obtained when the NH₃ flow rate was increased. When the flow rate of NH₃ was 15 sccm, Moiré fringes were observed in the TiN film as determined by TEM analysis. The intrinsic strain was found in the TiN film as deposited with 60 sccm NH₃.     

Investigation of DTS effect on r.f. magnetron sputtered ZnO thin films

The aim of this study depends on understanding the effect of target‐to‐substrate distance (D_TS) on ZnO thin films deposited by r.f. magnetron sputtering on to glass substrates at room temperature conditions. The D_TS was changed from 35 mm to 65 mm with steps of 5 mm at 165 W and 0.2 Pa. The deposition rate of the films were ranged from 76 Ǻ / min to 146 Ǻ / min, while 10^‐3 Ω.cm was obtained as the resistivity value with the help of four point probe technique. The structural investigations were carried out by using both the x‐ray diffraction (XRD) and high resolution transmission electron microscopy. According to XRD observations, the films were (002) oriented. Surface behaviour of the ZnO films was examined with atomic force microscopy and scanning electron microscopy. The root mean square (RMS) values were varied from 4.6 nm to 22.8 nm. Also, optical properties were obtained from UV–visible spectrophotometer and the transmittances as around 80 %. At 45 mm D_TS value, the minimum resistivity measured as 9 × 10^{− 4} Ω.cm with 76 Ǻ / min deposition rate. The RMS was obtained as 4.9 nm and transmission was measured as 85.30 %, while band gap was 3.45 eV.     

The influence of N2 flow rate and substrate temperature on Ti1‐xAlxN thin films

Titanium aluminium nitride (Ti_1‐xAl_xN) films have been deposited on silicon (111) substrate at a N₂ flow rate of 2 sccm and 20 sccm and at a substrate temperature of 773 K and at a N₂ flow rate of 2 sccm and at a substrate temperature of 873 K by reactive DC magnetron sputtering technique. The effect of N₂ flow rate and substrate temperature on the grain size and surface roughness of the deposited films have been investigated. The films have been analysed by X‐ray diffraction (XRD) and atomic force microscopy (AFM). The films were found to be nanocrystalline. While the grain size of the films decreases with increasing N₂ flow rate and decreases with increasing substrate temperature, the surface roughness of the films decreases with increasing N₂ flow rate and increases with increasing temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)