碲化铋红外透明导电薄膜的制备与光电性能(特邀)

Preparation and Photoelectric Properties of Bi2Te3 Infrared Transparent Conductive Films(Invited)

采用射频磁控溅射法在石英衬底和硒化锌衬底上制备了碲化铋薄膜,分别研究了薄膜厚度、退火温度对薄膜微观结构和光电性能的影响。利用X射线衍射仪、X射线光电子能谱仪和冷场发射扫描电子显微镜,分析了薄膜结构、成分和形貌。结果表明,退火有利于薄膜的结晶,且不改变晶体的择优取向。傅里叶变换红外光谱测试结果表明,在石英衬底和硒化锌衬底上沉积的薄膜,光学透过率随着薄膜厚度和退火温度的增加而减小,在硒化锌衬底上沉积的薄膜透过波段比石英长,且光学透过率更加稳定。霍尔效应测试结果表明,随着薄膜厚度和退火温度的增加,薄膜的电阻率逐渐减小,最小为1.448×10-3Ω·cm,迁移率为27.400 cm2·V-1·s-1,载流子浓度为1.573×1020cm-3。在石英衬底上沉积的15 nm厚的Bi2Te3薄膜,在1~5μm波段的透过率达到80%,退火200℃后透过率达到60%,电阻率为5.663×10-3Ω·cm。在硒化锌衬底上沉积相同厚度的薄膜,在2.5~20μm波段的透过率达到65%,200℃退火后透过率达到60%,薄膜电阻率为9.919×10-3Ω·cm。制备的Bi2Te3薄膜具有优良的光电特性,是红外透明导电薄膜领域理想的候选材料之一,在红外光电子学芯片制备领域有较好的应用前景。

Infrared transparent conductive thin film is a special material that can both transmit light and conduct electricity.It is widely used in solar cells,radiative cooling,infrared detector anti-interference coating,transparent electrode,sensing technology,photoelectric devices and other fields.Bismuth telluride is a semiconductor material with a molecular formula of Bi2Te3,which has good conductivity and a band gap width of 0.145 eV at room temperature.Based on the excellent optoelectronic properties of Bi2Te3 materials and their significant research value in the field of broadband photodetectors,Bi2Te3 is one of the ideal candidate materials in the field of infrared transparent conductive films.The preparation methods of Bi2Te3 films usually include pulsed laser deposition,magnetron sputtering,physical vapor transport,vacuum evaporation,molecular-beam epitaxy,electron beam deposition,etc.In this paper,Bi2Te3 thin films are deposited on fused silicas substrates and zinc selenide substrate by magnetron sputtering.The structure,composition and morphology of the prepared Bi2Te3 thin films are analyzed by diffractometer,X-ray photoelectron spectrometer and cold field emission scanning electron microscope.The optical transmittance,conductivity,carrier mobility and other optoelectronic properties of the films are studied.The test results show that annealing is conducive to the crystallization of the films,and does not change the preferred orientation of the crystals.The crystallinity is excellent when the annealing temperature is 350℃,and the crystallinity will become better with the increase of the film thickness.The Fourier transform infrared spectrum test results show that the optical transmittance of Bi2Te3 films deposited on fused silicas and zinc selenide substrates decreases with the increase of film thickness and annealing temperature.The optical transmittance of the films deposited on zinc selenide substrates is longer than that of fused silicas,and the optical transmittance is more stable.The hall effect test results indicate that with the increase of film thickness and annealing temperature,the resistivity of Bi2Te3 film gradually decreases,and the minimum resistivity of the prepared Bi2Te3 film is 1.448×10−3Ω·cm,with a mobility of 27.400 cm2·V−1·s−1 and a carrier concentration of 1.573×1020 cm−3.The Bi2Te3 thin film deposited on fused silicas substrate has a maximum transmittance of 80%in the 1~5μm infrared band,with a thickness of 15 nm.After annealing at 200℃,the transmittance can reach 60%and the resistivity is 5.663×10−3Ω·cm.The maximum transmittance of Bi2Te3 thin film with thickness of 15 nm deposited on zinc selenide substrate in 2.5~20μm infrared band reaches 65%,and after annealing at 200℃,the transmittance can reach 60%.At this time,the resistivity of the film is 9.919×10−3Ω·cm,with good photoelectric performance.Taking into account the photoelectric performance of the prepared thin film,when the thickness of the Bi2Te3 thin film is 15 nm and the annealing temperature is 200℃,the film has the excellent photoelectric comprehensive performance.Bi2Te3 thin films deposited on fused silicas and zinc selenide substrates have good photoelectric properties,which have potential applications in infrared detectors and anti-interference.