红外探测器用PbSe薄膜的研究现状

PbSe薄膜作为一种窄禁带半导体材料,因其具有优异的室温光电敏感性和响应度而被广泛用于制造硒化铅红外探测器。本文归纳和总结了PbSe薄膜的性能特点、制备工艺、后期处理工艺、理论研究方向以及国内外PbSe红外探测器的研究现状等内容,并在此基础上,探讨了PbSe红外探测薄膜材料及器件未来可能的发展方向。     

钛掺杂对Ge2Sb2Te5薄膜相变特性的改善

利用椭偏光谱术与XRD对钛掺杂Ge2Sb2Te5薄膜中钛元素对体系的光学性质及其微结构的影响进行了实验研究。进而对该薄膜进行的变温阻抗实验表明,钛掺杂Ge2Sb2Te5薄膜与未掺杂的薄膜相比具有更好的热稳定性。基于对薄膜样品的数据保持能力测试的实验数据,经阿伦纽斯外推处理可知,钛掺杂Ge2Sb2Te5薄膜样品的10年数据保持温度要高于未掺杂Ge2Sb2Te5薄膜样品。本文的实验结果均证实,钛掺杂Ge2Sb2Te5薄膜更适合应用于相变随机存取存储器中。     

双层CdS／CdSe光电导薄膜的制作和光电特性

提出并采用真空热蒸发技术制备了一种新型的多元掺杂（Ｃｌ，Ｃｕ）敏化的ＣｄＳ／ＣｄＳｅ双层光电导薄膜。研究了这种光电导薄膜的暗电导和亮电导、响应时间，以及光谱响应等主要光电特性与初始材料比例、掺杂浓度和Ｃｌ／Ｃｕ比例等工艺参数的关系。实验表明：适宜的掺杂浓度和Ｃｌ／Ｃｕ比例可使暗电导降低而亮暗电导比提高，响应时间比未掺杂薄膜的显著降低；而光谱响应特性则可以通过控制ＣｄＳ／ＣｄＳｅ之比加以优化。     

In掺杂ZnO透明导电薄膜光电性质的研究

采用射频磁控溅射技术成功制备出无掺杂和In掺杂的ZnO透明导电薄膜.研究了In掺杂对薄膜的结构和光电性能的影响.结果表明,In掺杂有利于提高ZnO薄膜结晶度,使薄膜表面更加致密平整;由于In3+替代了Zn2+,提供了大量的剩余电子,使薄膜的导电性质得到了很大的提高,所得薄膜的最小电阻率为4.3×10-3Q·cm.制备的ZnO薄膜在可见光范围的透过率达到了85%,In的掺杂对透光率的影响不大.     

掺Te 的GaSb薄膜分子束外延生长及缺陷特性

分析了非掺GaSb材料及在GaAs衬底上用分子束外延生长掺杂Te的GaSb薄膜材料的缺陷特性,主要应用正电子湮没多谱勒展宽谱方法,并结合原子力显微镜和X射线衍射测试进行.多谱勒展宽谱研究表明,采用分子束外延法生长的掺杂Te的n型半导体GaSb薄膜材料的S参数比体材料小,所得缺陷主要是单空位与间隙原子,而几乎无复合体的缺陷类型.     

二氧化钒多晶薄膜的掺杂改性

掺杂能明显改变二氧化钒薄膜的相变温度,影响其电学和光学性质。研究表明：W、Mo等大尺寸原子掺杂可以有效降低相变温度,而Al、P等小尺寸原子掺杂则使相变温度升高。综述、比较了不同掺杂方法和掺杂元素对相变、相变滞豫、电阻和透射性能的影响,介绍了用离子束增强沉积方法对二氧化钒薄膜掺杂改性的优点。综合分析表明,通过对二氧化钒多晶薄膜的掺杂改性,将相变温度降至室温附近,可以大大提高薄膜的室温电阻温度系数。     

硅基PbSe／BaF2／CaF2薄膜及其光电特性

采用分子束外延方法在Si(111)衬底上生长了PbSe/BaF2/CaF2薄膜,扫描电镜和X－光衍射分析显示,通过生长BaF2/CaF2缓冲层的方法,在Si(111)衬底上外延的PbSe薄膜晶体质量高,PbSe表面光亮,无形裂现象发生,X－光衍射峰峰宽窄（153arcs)。外延生长的PbSe薄膜被应用于制作光电二极管,首次采用热蒸发金属铝膜在PbSe表面形成Al-PbSe肖特基结光电二极管,获得了比Pb-PbSe肖特基结更为稳定和理想的电流－电压特性曲线。     

掺杂VO2薄膜的制备及其光电性质

以石英片为基底,采用直流/射频磁控共溅射法制备了掺A、掺Ti的V02薄膜.对所制样品进行了电阻-温度关系、原子力显微镜、透射光谱等光电性能测试.结果分析表明,Al元素可以提高薄膜相变温度及Ti元素可以有效提高相变前后电阻率变化幅度,并且用半导体能带理论对VO2薄膜光电性质改变的原因及掺杂对其造成的影响予以解释,提出了影响相变滞豫的原因及改善方法.最后对磁控共溅射沉积方法制备掺杂薄膜的工艺方法提出了改进.     

未掺杂CdZnTe与掺铟CdZnTe晶体的热处理

对于未掺杂Cd0.9Zn0.1Te晶片,采用在Cd/Zn气氛下,以In作为气相掺杂源进行热处理;而对于低阻In-Cd0.9Zn0.1Te晶片,则采用在Te气氛下进行热处理.分别研究了不同的热处理条件,包括温度、时间、pIn或pTe等对晶片电学性能、红外透过率以及Te夹杂/沉淀相的影响.结果表明,在Cd/Zn气氛下适当的掺In热处理和在Te气氛下适当的热处理均有效地提高了晶片的电阻率,分别达到2.3×1010和5.7×109Ω·cm,同时晶片的其他性能也得到明显改善.     

未掺杂CdZnTe与掺铟CdZnTe晶体的热处理

对于未掺杂Cd0.9Zn0.1Te晶片,采用在Cd/Zn气氛下,以In作为气相掺杂源进行热处理;而对于低阻In-Cd0.9Zn0.1Te晶片,则采用在Te气氛下进行热处理.分别研究了不同的热处理条件,包括温度、时间、pIn或pTe等对晶片电学性能、红外透过率以及Te夹杂/沉淀相的影响.结果表明,在Cd/Zn气氛下适当的掺In热处理和在Te气氛下适当的热处理均有效地提高了晶片的电阻率,分别达到2.3×1010和5.7×109Ω·cm,同时晶片的其他性能也得到明显改善.     

脉冲激光双光束沉积掺Mg的GaN薄膜的研究

采用脉冲激光双光束沉积系统在Si(111)衬底上生长了掺Mg的GaN薄膜和未掺杂GaN薄膜。利用X射线衍射(XRD)、原子力显微镜(AFM)、室温范德堡霍尔测量及光致发光(PL)光谱对两类薄膜进行对比分析，结果显示，所生长的GaN薄膜均为六方纤锌矿晶体结构，掺Mg可细化所生长的GaN薄膜晶粒。随着掺Mg量的增加，GaN薄膜无需后处理即可由”型导电转化为p型导电，GaN薄膜的光学性能随p型载流子浓度增大而提高；然而掺Mg却导致GaN薄膜结晶质量下降，掺镁量过大的GaN薄膜中p型载流子浓度反而减少，光致发光中黄发射峰增强较大。研究表明通过优化脉冲激光双光束沉积参数无需任何后处理可直接获得高空穴载流子浓度的p型GaN薄膜。     

Highly Conducting Transparent Indium-Doped Zinc Oxide Thin Films

Highly conducting transparent indium-doped zinc oxide (IZO) thin films have been achieved by controlling different growth parameters using radio frequency magnetron sputtering. The structural, electrical, and optical properties of the IZO thin films have been investigated for varied indium content and growth temperature (T _G) in order to find out the optimum level of doping to achieve the highest conducting transparent IZO thin films. The highest mobility and carrier concentration of 11.5 cm²/V-s and 3.26 × 10²⁰ cm^?3, respectively, have been achieved in IZO doped with 2% indium. It has been shown that as T _G of the 2% IZO thin films increase, more and more indium atoms are substituted into Zn sites leading to shift in (002) peaks towards higher angles which correspond to releasing the stress within the IZO thin film. The minimum resistivity of 5.3 × 10^?4 Ω-cm has been achieved in 2% indium-doped IZO grown at 700°C.     

光伏新材料a-CN_x薄膜的光电响应性质

采用离子束溅射反应沉积技术,以高纯N2 为工作气体,利用在不同气压下产生的离子束轰击石墨靶,在石英基片上溅射出的碳原子与氮离子反应,沉积出a- CNx 薄膜.在室温下,研究薄膜的暗电导和在卤素光源照射下的光电导、光响应增益、响应时间等性质,以及制备工艺和掺杂、氢化对这些性质的影响及关系.实验结果表明:未掺杂的a- CNx 薄膜的光响应增益达1 8,磷掺杂薄膜的光响应增益为3.0 ,经过氢化处理的未掺杂a- CNx 薄膜的光响应增益为30 ,光响应时间大约为30 0 s.     

Structural, Optical, and Electrical Properties of Nb-Doped ZnO Thin Films Prepared by Spray Pyrolysis Method

Niobium (Nb) doping (0 at.% to 3 at.%) in ZnO thin films prepared by the chemical spray pyrolysis method at a substrate temperature of 400°C enhances the optical and electrical properties but deteriorates the structural quality of the films. The films are polycrystalline with hexagonal structure having a preferential orientation along the (002) crystallographic direction. The film doped with 3 at.% Nb demonstrates a maximum average transmittance of ~83% in the visible region. A strong blue emission is recorded for both pure and doped films, and the intensity is substantially enhanced with Nb doping due to interface and valence-band transitions. Vacuum annealing at 400°C for 60 min improves the electrical characteristics of the films, and the highest mobility of 71 cm²/V s is achieved for the 1 at.% Nb-doped ZnO films.     

Gd掺杂BiFeO3薄膜的溶胶-凝胶法制备和电性能研究

利用溶胶-凝胶工艺在ITO/玻璃衬底上制备了Bi1-xGdxFeO3(x=0.00、0.05、0.10和0.15)薄膜.研究了Gd掺杂对薄膜的结构、形貌、漏电流性能和介电性能的影响.结果显示,未掺Gd和Gd掺杂为5％的样品为菱方结构,当Gd掺杂量达到10％和15％时,样品变为四方结构.掺10％Gd的薄膜样品表面光滑、平整,晶粒大小均匀.Gd的掺入大大降低了BiFeO3(BFO)薄膜的漏电流,其中掺Gd量为10％和15％的薄膜的漏电流几乎为零.在整个测试频率范围内,掺10％Gd的样品的介电常数较大且能保持恒定,同时其介电损耗最小.     

Bismuth Doping–Induced Stable Seebeck Effect Based on MAPbI3 Polycrystalline Thin Films

In this article, the thermoelectric properties of a Bi‐doped CH₃NH₃PbI₃ (MAPbI₃) perovskite thin film are studied. Bi‐doped MAPbI₃ thin film samples are fabricated, and it is found that Bi doping could greatly enhance the stability and thermoelectric properties of MAPbI₃. The Bi dopant located at the grain boundaries to modify the carrier channel near grain boundaries, which is observed via scanning electron microscopy and atomic force microscopy, efficiently reduces ion migration and facilitates charge transport. In addition, the Bi dopant can also passivate the defects in bulk MAPbI₃, increasing the polarization effect of MAPbI₃ which is demonstrated by the capacitance‐frequency measurement, thus greatly enhancing the mobility of Bi‐doped MAPbI₃. In addition, Bi‐doped MAPbI₃ leads to grain size reduction; the small size effect not only effectively hinders the MAPbI₃'s crystal phase transition from the tetragonal phase to the cubic phase, but it could also make the structure of MAPbI₃ more stable. Especially, the Seebeck voltage variation of Bi‐doped perovskite was less than that of the undoped one, meaning Bi doping would lead to a much more stable state in MAPbI₃ thin films. The results show that Bi‐doped MAPbI₃ is a promising approach to develop high stable thermoelectric and photovoltaic properties in organic–inorganic hybrid perovskite materials.     

Thermoelectric Properties of Ag-doped Mg<Subscript>2</Subscript>Ge Thin Films Prepared by Magnetron Sputtering

Silver doped p-type Mg₂Ge thin films were grown in situ at 773 K using magnetron co-sputtering from individual high-purity Mg and Ge targets. A sacrificial base layer of silver of various thicknesses from 4 nm to 20 nm was initially deposited onto the substrate to supply Ag atoms, which entered the growing Mg₂Ge films by thermal diffusion. The addition of silver during film growth led to increased grain size and surface microroughness. The carrier concentration increased from 1.9 × 10¹⁸ cm⁻³ for undoped films to 8.8 × 10¹⁸ cm⁻³ for the most heavily doped films, but it did not reach saturation. Measurements in the temperature range of T = 200–650 K showed a positive Seebeck coefficient for all the films, with maximum values at temperatures between 400 K and 500 K. The highest Seebeck coefficient of the undoped film was 400 μV K⁻¹, while it was 280 μV K⁻¹ for the most heavily doped film at ∼400 K. The electrical conductivity increased with silver doping by a factor of approximately 10. The temperature effects on power factors for the undoped and lightly doped films were very limited, while the effects for the heavily doped films were substantial. The power factor of the heavily doped films reached a non-optimum value of ∼10⁻⁵ W cm⁻¹ K⁻² at 700 K.     

Properties of nanostructured Al doped ZnO thin films grown by spray pyrolysis technique

Aluminium doped zinc oxide thin films were deposited on glass substrate by using spray pyrolysis technique. The X-ray diffraction study of the films revealed that the both the undoped and Al doped ZnO thin films exhibits hexagonal wurtzite structure. The preferred orientation is (002) for undoped and up to 3 at % Al doping, further increase in the doping concentration to 5 at % changes the preferred orientation to (101) direction. The surface morphology of the films studied by scanning electron microscope, reveal marked changes on doping. Optical study indicates that both undoped and Al doped films are transparent in the visible region. The band gap of the films increased from 3.24 to 3.36 eV with increasing Al dopant concentration from 0 to 5 at % respectively. The Al doped films showed an increase in the conductivity by three orders of magnitude with increase in doping concentration. The maximum value of conductivity 106.3 S/cm is achieved for 3 at % Al doped films.     

掺杂Al对DC反应溅射ZnO薄膜的影响

采用金属单质靶和直流反应溅射制备了不同Al含量(摩尔分数)掺杂的ZnO薄膜,得到的薄膜均为c-轴择优取向的纤锌矿结构,在可见波段具有很高的透过率。薄膜的晶面间距、光学折射率和带隙在掺Al的起始阶段变化很大,待Al掺杂量达到一定值后,光学折射率和带隙的变化不大,薄膜的晶面间距趋于一稳定值0.266 nm。分析表明掺杂的Al均作为施主对载流子浓度作出了贡献,影响薄膜导电性能的主要原因被推断为晶格中的缺陷等因素导致了载流子的局域束缚。     

PECVD制备非晶硅薄膜的研究

实验采用等离子体增强化学气相沉积(PECVD)法在Si衬底上制备了非晶硅薄膜。研究了射频功率、PH3掺杂浓度等因素对薄膜电阻率以及应力的影响。实验结果表明,对于非掺杂非晶硅薄膜,当射频功率从15W增加到45W时,薄膜应力从张应力变化到压应力,在射频功率为35W时,应力几乎为零,应力绝对值先降低后增加,淀积速率随着射频功率的增加而增加;对于掺杂非晶硅薄膜,电阻率随着PH3掺杂浓度的增加而降低,当PH3流量从0cm3/min增加到12cm3/min时,薄膜掺杂效果明显,电阻率降低3个数量级,继续增加PH3流量,电阻率变化较小,而应力随着PH3掺杂浓度的增加而降低,当PH3流量超过12cm3/min时,应力有增加的趋势。