Optical and Chemical Function Developments for Oxide Semiconductor Device using Substrate of Oriented Zinc Oxide Crystal

采用气相输运法制备了高度取向的氧化锌晶体。以该晶体为衬底制备了氧化物半导体器件。氧化锌是一种宽禁带宽度(3.2 eV)的n型半导体。氧化锶(SrCu2O_2)是一种宽禁带宽度(3.1 eV)的p型半导体。本工作采用镜面抛光法制备了氧化锌晶体的衬底，并采用PLD和溅射法制备了SrCu2O2薄膜。用PLD方法制备的p-n结具有发射紫外光的LED特性。利用晶轴取向的氧化锌块材，我们可以选择三种表面，即锌、氧和A面。锌面和O面是极性面，A面(平行于c轴)是非极面。每个面在结构和电气上都有不同的特点。使用O-Fess可以获得最高的整流特性。对该装置的气敏特性进行了测试。该装置不仅显示了氢气和一氧化碳的传感特性，而且显示了甲苯的传感特性。对挥发性有机化合物(VOC)气体甲苯的检测表明，这种由宽带隙半导体氧化物p-n结组成的器件具有很高的氧化能力。还制备了高电阻率的氧化锌晶体电致发光器件。用硅酸锌：锰薄膜作为发光体。氧化锌具有较高的电阻率，具有压电性。虽然这种器件应该表现出由压电振动调节的电致发光特性，但还没有得到足够的发光。

Highly oriented zinc oxide crystal was prepared by applying vapor transport method. The oxide semiconductor device was prepared using this crystal as a substrate.Zinc oxide is an n-type semiconductor with wide band gap (3.2 eV). Strontium cupper oxide (SrCu_2O_2) is p-type semiconductor with wide band gap (3.1 eV). In this work, the substrate was prepared by mirror finishing the ZnO crystal, and SrCu_2O_2 thin film was obtained by PLD or sputtering method. The p-n junction prepared by PLD method showed LED characteristic emitting UV light. By using crystal axis oriented ZnO bulk, we can select 3 kinds of surface, Zn-,O- and A-face. The Zn- and the O- faces are polar faces and the A-face (parallel to c-axis) is a non-polar fece. Each face has different characteristic structurally and electrically. Using the O-fece, the highest rectifying characteristic was obtained. The gas sensing property of this device was measured. This device showed the sensing characteristic not only hydrogen and carbon monoxide but also toluene. Detecting the VOC(volatilizing organic compound) gas as toluene indicates the high oxidizing ability of this device composed by p-n junction of semiconducting oxides with the wide band gap.The EL device using ZnO crystal with high resistivity was also prepared. ZnSiO_4:Mn thin film was employed as a luminous. ZnO with high resistivity shows piezo-electric property. Though this device should show the EL property tuned by piezo-electric vibration, the enough luminescence has not been obtained.