发光学报, 2018, 39 (7): 942, 网络出版: 2018-08-30
MBE法制备VO2薄膜及其中红外调制深度测量
VO2 Thin Films Prepared by MBE and Measurements of Mid-infrared Modulation Depth
分子束外延 VO2薄膜 透过率调制深度 中红外激光防护 molecular beam epitaxy(MBE) VO2 thin films transmittance modulate depth mid-infrared laser protection
摘要
为了给VO2薄膜在定向红外对抗系统防护方面的应用提供理论依据, 我们用透过率调制深度表征VO2薄膜在中红外波段的相变特性。本实验利用分子束外延法(MBE)制备VO2外延单晶薄膜, 经XRD、AFM表征, 发现其具有(020)择优取向、纯度较高, 薄膜表面平整、均匀且致密。经VU-Vis-IR测量发现其近红外透过率相变特性显著, 但在紫外和可见光范围内透过率相变特性较不明显。然后我们对制备时间为30 min、40 min的两组薄膜分别进行25~70 ℃的升温和降温实验, 观察其对波长为3 459 nm、脉宽50 ns、重频50 kHz、功率密度0.14 W/cm2的中红外激光的透过率变化, 并比较两组薄膜的温滞曲线特性。实验发现它们对中红外透过率的调制深度均可达60%以上, 前者比后者对中红外的调制深度高出约4%。这说明利用分子束外延法制备的VO2单晶薄膜具有良好的中红外调制特性, 且调制深度和膜厚有关。进一步表明了利用VO2薄膜实现中红外激光防护具有一定的可行性。
Abstract
In order to provide the theoretical basis for the application of VO2 thin films to anti-directional infrared countermeasures system, the phase transition characteristics of VO2 thin films in the infrared band were characterized by the transmittance modulation depth. At first, VO2 epitaxial mono crystalline thin films were prepared by molecular beam epitaxy(MBE), and then characterized by X-ray diffraction(XRD), atomic force microscope(AFM). It is found that it has (020) preferential orientation, high purity VO2 in the thin films, the surface of thin films is smooth, uniform and dense. The near infrared transmittance phase transmittance property is found to be outstanding by VU-Vis-IR measurement, however, it is less obvious in ultraviolet and visible light. We took an experiment that transmittance variation for mid-infrared from 25 to 70 ℃ temperature rising and cooling process based on two groups of VO2 prepared for 30 min and 40 min, respectively. The mid-infrared laser was used in the experiment with 3 459 nm wavelength, 50 ns pulse width, 50 kHz repetition frequency, and 0.14 W/cm2 power density. The two temperature hysteresis curves were compared. It is found that the transmittance modulation depth of mid-infrared of them both can reach over 60%, and the former group is about 4% higher than the latter group in transmittance modulation depth in mid-infrared. This indicates that the VO2 mono crystalline films prepared by the molecular beam epitaxial method have good mid-infrared transmittance modulation characteristics, and the modulation depth is related to film thickness. It is further demonstrated that it is feasible to put VO2 thin films into anti-directional infrared countermeasures system.
刘志伟, 路远, 侯典心, 邹崇文. MBE法制备VO2薄膜及其中红外调制深度测量[J]. 发光学报, 2018, 39(7): 942. LIU Zhi-wei, LU Yuan, HOU Dian-xin, ZOU Chong-wen. VO2 Thin Films Prepared by MBE and Measurements of Mid-infrared Modulation Depth[J]. Chinese Journal of Luminescence, 2018, 39(7): 942.