Tadeo Inyalot Jude, Mukhokosi Emma P, Krupanidhi Saluru B, Umarji Arun M
Materials Research Centre, Indian Institute of Science Bengaluru 560012 India
RSC Adv. 2019 Mar 29;9(18):9983-9992. doi: 10.1039/c9ra00189a. eCollection 2019 Mar 28.
We report detailed structural, electrical transport and IR photoresponse properties of large area VO(M1) thin films deposited by a simple cost-effective two-step technique. Phase purity was confirmed by XRD and Raman spectroscopy studies. The high quality of the films was further established by a phase change from low temperature monoclinic phase to high temperature tetragonal rutile phase at 68 °C from temperature dependent Raman studies. An optical band gap of 0.75 eV was estimated from UV-visible spectroscopy. FTIR studies showed 60% reflectance change at = 7.7 μm from low reflectivity at low temperature to high reflectivity at high temperature in a transition temperature of 68 °C. Electrical characterization showed a first order transition of the films with a resistance change of four orders of magnitude and TCR of -3.3% K at 30 °C. Hall-effect measurements revealed the n-type nature of VO thin films with room temperature Hall mobility, of 0.097 cm V s, conductivity, of 0.102 Ω cm and carrier concentration, = 5.36 × 10 cm. In addition, we fabricated a high photoresponsive IR photodetector based on VO(M1) thin films with excellent stability and reproducibility in ambient conditions using a low-cost method. The VO(M1) photodetector exhibited high sensitivity, responsivity, quantum efficiency, detectivity and photoconductive gain of 5.18%, 1.54 mA W, 0.18%, 3.53 × 10 jones and 9.99 × 10 respectively upon illumination with a 1064 nm laser at a power density of 200 mW cm and 10 V bias voltage at room temperature.
我们报告了通过一种简单且经济高效的两步技术沉积的大面积VO(M1)薄膜的详细结构、电输运和红外光响应特性。通过X射线衍射（XRD）和拉曼光谱研究确认了相纯度。通过温度相关拉曼研究表明，薄膜在68°C时从低温单斜相转变为高温四方金红石相，进一步证实了薄膜的高质量。通过紫外可见光谱估计光学带隙为0.75 eV。傅里叶变换红外光谱（FTIR）研究表明，在68°C的转变温度下，从低温时的低反射率到高温时的高反射率，在波长为7.7μm处反射率变化了60%。电学表征显示薄膜发生一级转变，电阻变化四个数量级，在30°C时的电阻温度系数（TCR）为-3.3%/K。霍尔效应测量揭示了VO薄膜的n型性质，室温下霍尔迁移率为0.097 cm² V⁻¹ s⁻¹，电导率为0.102 Ω⁻¹ cm⁻¹，载流子浓度为5.36×10¹⁹ cm⁻³。此外，我们使用低成本方法制造了一种基于VO(M1)薄膜的高光响应红外光电探测器，在环境条件下具有出色的稳定性和可重复性。在室温下，用功率密度为200 mW/cm²的1064 nm激光照射并施加10 V偏置电压时，VO(M1)光电探测器分别表现出5.18%、1.54 mA/W、0.18%、3.53×10¹¹ jones和9.九九×10⁵的高灵敏度、响应度、量子效率、探测率和光电导增益。 （注：原文中“九九”可能有误，推测为“9.99”）
