磁控溅射制备纳米晶GZO/CdS双层膜及GZO/CdS/p-Si异质结光伏器件的研究

采用磁控溅射制备Ga掺杂ZnO (GZO)/CdS双层膜在p型晶硅衬底上以形成GZO/CdS/p-Si异质结器件。纳米晶GZO/CdS双层膜的微结构、光学及电学特性,通过XRD、SEM、XPS、紫外-可见光分光光度计和霍尔效应测试系统表征。GZO/CdS/p-Si异质结J-V曲线显示良好的整流特性。在±3 V时,整流比IF/IR(IF和IR分别表示正向和反向电流)已达到21。结果表明纳米晶GZO/CdS/p-Si异质结具有好的二极管特性,在反向偏压下获得高光电流密度。纳米晶GZO/CdS/p-Si异质结显示明显的光伏特性。由于CdS晶格常数在GZO和晶Si之间,它能作为一个介于GZO和晶Si之间的缓冲层,能有效地减少GZO和p-Si之间的界面态。因此,我们获得了GZO/CdS/p-Si异质结明显光伏特性。     

射频磁控溅射法制备AZO/p-Si异质结及其性能研究

利用射频磁控溅射法,在p-Si衬底上生长了Al掺杂的ZnO(AZO)薄膜,并进而制备了AZO/p-Si异质结。X射线衍射仪、紫外-可见光分光光度计、四探针测试仪和霍尔效应测试仪测量表明,AZO薄膜具有良好的结晶质量、光学和电学特性。暗态下的I-V测试表明,AZO/p-Si异质结具有较好的整流特性,反向饱和电流为1.29×10-6A,±2V处的正向和反向电流之比为229.41,计算得出异质结的理想因子为2.28。在标准光照下AZO/p-Si异质结呈现出明显的光生伏特效应,这种异质结太阳电池具有2.51%的光电转换效率。     

n-ZnO/p-Si异质结J-V特性的实验研究

本文首次报道n-ZnO/p-Si异质结J－V特性实验测量的初步结果－经退火处理的异质结反向饱和电流密度比未经退火的减少一个数量级,表明退火改善ZnO／Si晶格界面结构,提高了n-ZnO/p-Si异质结性能。     

3C-SiC/Si异质结二极管的高温特性

研究了低压化学气相淀积方法制备的n-3C-SiC/p-Si(100)异质结二极管(HJD)在300～480K高温下的电流密度-电压(J-V)特性.室温下HJD的正反向整流比(通常定义为±1V外加偏压下)最高可达1.8×104,在480K时仍存在较小整流特性,整流比减小至3.1.在300K温度下反向击穿电压最高可达220V.电容-电压特性表明该SiC/Si异质结为突变结,内建电势Vbi为0.75V.采用了一个含多个参数的方程式对不同温度下异质结二极管的正向J-V实验曲线进行了很好的拟和与说明,并讨论了电流输运机制.该异质结构可用于制备高质量异质结器件,如宽带隙发射极SiC/Si HBT等.     

3C-SiC/Si异质结二极管的高温特性

研究了低压化学气相淀积方法制备的n-3C-SiC/p-Si(100)异质结二极管(HJD)在300～480K高温下的电流密度-电压(J-V)特性.室温下HJD的正反向整流比(通常定义为±1V外加偏压下)最高可达1.8×104,在480K时仍存在较小整流特性,整流比减小至3.1.在300K温度下反向击穿电压最高可达220V.电容-电压特性表明该SiC/Si异质结为突变结,内建电势Vbi为0.75V.采用了一个含多个参数的方程式对不同温度下异质结二极管的正向J-V实验曲线进行了很好的拟和与说明,并讨论了电流输运机制.该异质结构可用于制备高质量异质结器件,如宽带隙发射极SiC/Si HBT等.     

p-CuAlO2/(n-, p-)Si异质结的制备与电学性质

采用化学溶液法在n型和p型Si衬底上成功制备了单相CuAlO2薄膜。薄膜的电导率-温度曲线显示,薄膜在200K-300K温度范围内呈热激活导电模式,激活能约为0.3eV。电流-电压特性测试显示,p-CuAlO2/n-Si异质结具有明显的整流特性,开启电压约为1.6V,在±3V处的整流率约为35,而p-CuAlO2/p-Si同型异质结表现出类似肖特基结的电学性质,由于p-CuAlO2导电性远低于p-Si衬底,正向电流受空间电荷限制。     

TiO2/n-Si/p-Si及n-PS/p-PS/Si的光伏特性

在抛光的p型单晶硅上通过扩散工艺制备pn结,采用此种硅片利用阳极腐蚀法制备多孔硅(PS).用磁控溅射镀膜机在有pn结的单晶硅表面镀上一层TiO2纳米结构薄膜,并用表面光电压谱(SPS)研究了n-PS/p-PS/Si和TiO2/n-Si/p-Si的表面光伏特性.结果表明TiO2/n-Si/p-Si和n-PS/p-PS/Si的光伏效应比n-Si/p-Si在不同程度上有所提高.在300～600 ℃热处理温度范围内TiO2/n-Si/p-Si的光伏效应随温度的升高而增强,600～800 ℃范围内随温度的升高而降低.     

无坑洞n-3C-SiC/p-Si(100)的LPCVD外延生长及其异质结构特性

在MBE/CVD高真空系统上,利用低压化学气相淀积(LPCVD)方法在直径为50mm的单晶Si(100)衬底上生长出了高取向无坑洞的晶态立方相碳化硅(3C-SiC)外延材料,利用反射高能电子衍射(RHEED)和扫描电镜(SEM)技术详细研究了Si衬底的碳化过程和碳化层的表面形貌,获得了制备无坑洞3C-SiC/Si的优化碳化条件,采用霍尔(Hall)测试等技术研究了外延材料的电学特性,研究了n-3C-SiC/p-Si异质结的I-V、C-V特性及I-V特性对温度的依赖关系.室温下n-3C-SiC/p-Si异质结二极管的最大反向击穿电压达到220V,该n-3C-SiC/p-Si异质结构可用于制备宽带隙发射极SiC/Si HBTs器件.     

3C-SiC/Si异质结二极管的高温特性

研究了低压化学气相淀积方法制备的n- 3C- Si C/p- Si(10 0 )异质结二极管(HJD)在30 0～4 80 K高温下的电流密度-电压(J- V)特性.室温下HJD的正反向整流比(通常定义为±1V外加偏压下)最高可达1.8×10 4 ,在4 80 K时仍存在较小整流特性,整流比减小至3.1.在30 0 K温度下反向击穿电压最高可达2 2 0 V .电容-电压特性表明该Si C/Si异质结为突变结,内建电势Vbi为0 .75 V.采用了一个含多个参数的方程式对不同温度下异质结二极管的正向J-V实验曲线进行了很好的拟和与说明,并讨论了电流输运机制.该异质结构可用于制备高质量异质结器件,如宽带隙发射极Si C/Si HBT     

ZnO/SiC/Si异质结的光电转换特性

我们利用直流溅射制备了一系列的n-ZnO/n-SiC/p-Si和n-ZnO/p-Si异质结,通过研究他们的结构、I-V曲线、光生伏特效应和光响应谱。并且研究了他们的光电转换特性。发现n-ZnO/n-SiC/p-Si异质结的光电转换效率大约是n-ZnO/p-Si异质结的四倍。n-ZnO/n-SiC/p-Si异质结的光响应曲线也比n-ZnO/p-Si异质结强,表明n-ZnO/p-Si异质结加入3C-SiC中间层后光响应明显增强。在表面光电流谱中n-ZnO/n-SiC/p-Si异质结观察到两个拐点,而n-ZnO/p-Si异质结只观察到一个。通过以上研究可以看出3C-SiC在n-ZnO/n-SiC/p-Si异质结的光电转换中起了很大的作用.     

The influence of substrate temperature on RF sputtered CdS thin films and CdS/p-Si heterojunctions

Cadmium sulfide (CdS) thin films were deposited onto soda lime glasses and p-Si semiconductors at various substrate temperatures (40, 150 and 275 °C) by radio frequency (RF) sputtering technique. The effect of substrate temperature on morphological, structural and optical properties of CdS thin films were analyzed by means of atomic force microscopy (AFM), x-ray diffraction (XRD) and uv–vis spectrum data. The results showed that the average roughness (R_a) of thin films increased from 2.0 to 4.0 nm and all films had hexagonal wurtzite structure. The optical band gaps of CdS thin films varied between 2.46–2.43 eV. Characteristic parameters of CdS/p-Si heterojunctions including ideality factor, barrier height, series resistance and rectification ratio were measured. It was seen that both ideality factor and barrier height values of the heterojunctions increase with the increase substrate temperature. It was attributed to increase in inhomogenity of the thin films. Furthermore, the photoelectrical parameters of CdS/p-Si heterojunctions were studied.     

简易化学水浴法制备SnO2/p-Si异质结光电性能

SnO2薄膜沉积在晶硅衬底上通过一种简单化学水浴法以制备n-SnO2/p-Si异质结光电器件,该化学水浴法非常便宜和方便。采用XRD、XPS、紫外-可见光分光光度计和霍尔效应测试系统表征了SnO2薄膜的微结构、光学和电学性能,对SnO2/p-Si异质结的I-V曲线进行测试并分析,获得明显的光电转换特性。     

真空退火温度对GZO/Ag/GZO三层膜性能的影响

室温下在玻璃衬底上,采用射频磁控溅射GZO(Ga掺杂ZnO)膜和离子束溅射Ag膜的方法,制备了GZO/Ag/GZO三层膜,分析了真空退火温度对样品结构、光学、电学性能的影响。结果显示:随着退火温度的升高,Ag层的结构得到明显改善,但GZO层结晶度受到了Ag扩散的影响。经过350℃退火后,样品在可见光区平均透射率达92.63%,电阻率由8.0×10–5Ω·cm降至4.0×10–5Ω·cm。     

Photoelectric conversion characteristics of ZnO/SiC/Si heterojunctions

A series ofn-ZnO/n-SiC/p-Si and n-ZnO/p-Si heterojunctions were prepared by DC sputtering. Their struc-tural properties, Ⅰ-Ⅴ curves, photovoltaic effects and photo-response spectra were studied. The photoelectric conver-sion characteristics of n-ZnO/n-SiC/p-Si and n-ZnO/p-Si heterojunctions were investigated. It is found that the pho-toelectric conversion efficiency of the n-ZnO/n-SiC/p-Si heterojunction is about four times higher than that of the n-ZnO/p-Si heterojunction. The photovoltaic response spectrum indicated that the photoresponse curve of n-ZnO/n-SiC/p-Si increased more strongly than that of n-ZnO/p-Si with the wavelength increasing. It shows that the photore-sponse ofn-ZnO/p-Si can be enhanced when inserting a 3C-SiC layer between ZnO and Si. There is one inflexion in the photocurrent response curve of the n-ZnO/p-Si heterojunction and two inflexions in that of the n-ZnO/n-SiC/p-Si het-erojunction. It is clear that the 3C-SiC plays an important role in the photoelectric conversion of the n-ZnO/n-SiC/p-Si heterojunction.     

硫掺杂纳米金刚石薄膜的图形化生长

利用电子增强热丝化学气相沉积(EACVD)技术,以CH4/H2/H2S/Ar为工作气体,SiO2/Si为衬底,制备了硫掺杂金刚石薄膜。研究了利用光刻技术实现薄膜的图形化生长。结果表明:以SiO2作掩模的光刻技术能够使得硫掺杂金刚石薄膜在光滑SiO2/Si基片上很好地图形化生长。Hall效应检测表明硫掺杂金刚石薄膜为n型,给出了n型金刚石/p-Si异质结的反向I-V特性曲线。     

ZnO/p-Si异质结的I-V及C-V特性研究

通过磁控溅射Al掺杂的ZnO陶瓷靶,在p-Si片上沉积n型电导的ZnO薄膜而制备了ZnO/p-Si异质结,并通过测试其光照下的I-V、C-V特性对其光电特性以及载流子输运特性与导电机理进行了研究。研究表明ZnO/p-Si异质结存在良好的整流特性与光电响应,可以广泛应用在光电探测和太阳电池等领域。由于在ZnO/p-Si异质结界面处的导带补偿与价带补偿相差太大的缘故,在正向电压超过1V时,导电机理为空间电荷限制电流导电。同时,研究表明ZnO/p-Si异质结界面存在大量界面态,可以通过减小界面态进一步提高其光电特性。     

X-ray imaging camera tube using sputter-deposited CdTe/CdSheterojunction

CdTe heterojunction devices have been fabricated for the first time by an RF sputter deposition method for application to X-ray imaging sensors. The electrical resistivities of sputter-deposited polycrystalline CdS and CdTe films are greater than 10⁶ Ω-cm and 10⁹ Ω-cm, respectively. The fabricated CdS/CdTe heterojunction sensor shows a good diode characteristic and a high sensitivity to X-ray radiation. An X-ray imaging camera tube consisting of CdS/CdTe heterojunction photoconductive target shows three times larger responsivity to X-rays than the conventional PbO X-ray tube. The dark current density of the device is observed to be lower than 10 nA/cm² at 20 V target voltage at room temperature     

Optical properties of CdS micro/nanocrystalline structures prepared via a thermal evaporation method

Cadmium sulfide (CdS) micro/nanocrystalline structures were fabricated by thermal evaporation in the absence of a catalyst on ITO-coated glass and Si(100) substrates. The samples prepared at 520 °C showed two structures of CdS: nanowires (NWs) and necklace-like microstructures grown on Si(111) and ITO substrates, respectively. The crystalline structures of the grown CdS necklace-like microstructures and NWs were studied using XRD analysis. The CdS necklaces and NWs structures were formed with hexagonal (wurtzite) structure. Two emission bands (green and red) were observed in the photoluminescence spectra of the prepared samples. The green PL emission in both structures showed a strong blue-shift compared with the optical band gap of CdS. Raman spectra of the grown CdS micro/nanocrystalline structures show redshift in the fundamental (1LO) and overtone (2LO) peaks location compared with Raman bands of bulk CdS.