Chemical spray pyrolysis deposition and characterization of p-type CuCr1−xMgxO2 transparent oxide semiconductor thin films
Chemical spray pyrolysis deposition and characterization of p-type CuCr1−xMgxO2 transparent oxide semiconductor thin films
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DOI：
10.1016/j.jpcs.2008.03.007
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发表时间：
2008-08
影响因子：
4
通讯作者：
S. H. Lim;S. Desu;A. Rastogi
中科院分区：
文献类型：
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作者：
S. H. Lim;S. Desu;A. Rastogi
介绍了一种利用金属有机前驱体制备p型掺镁CuCrO2透明氧化物半导体薄膜的化学喷雾热解技术。沉积时的薄膜含有混合尖晶石CuCr2O4和钙铁矿型CuCrO2结构相。在⩾70 0℃的Ar气氛中，实现了尖晶石CuCr2O4组分的还原和单相CuCrO2结构的高结晶性薄膜的形成。提出了喷射沉积法制备CuCrO2薄膜的机理，包括前驱体分解、氧化和组成氧化物之间的反应。热处理后的CuCr0.93Mg0.07O2薄膜具有较高的可见光透过率(⩾80%)和较强的带隙吸收，直接带隙为3.11 eV，间接带隙为2.58 eV。衬底温度较低(∼450℃)的薄膜为非晶态，晶化后产生较低的直接带隙(2.96 eV)和间接带隙(2.23 eV)。由Seebeck分析测得CuCr0.93-0.07O2薄膜的电导率为0.6-1Scm−1，空穴浓度∼为2×1019 cm−3。在300-470K温度范围内，电导率随温度变化的激活能∼为0.11 eV，在∼470K温度范围内的激活能为⩾0.23 eV，分别归因于激活电导和晶界陷阱辅助电导。制备了结构为Au/n-(ZnO)/p-(CuCr0.93Mg0.07O2)/SnO2(TCO)的异质结二极管，显示了其在宽禁带透明结器件中的应用前景。
A chemical spray pyrolysis technique for deposition of p-type Mg-doped CuCrO2transparent oxide semiconductor thin films using metaloorganic precursors is described. As-deposited films contain mixed spinel CuCr2O4and delafossite CuCrO2structural phases. Reduction in spinel CuCr2O4fraction and formation of highly crystalline films with single phase delafossite CuCrO2structure is realized by annealing at temperatures ⩾700°C in argon. A mechanism of synthesis of CuCrO2films involving precursor decomposition, oxidation and reaction between constituent oxides in the spray deposition process is presented. Post-annealed CuCr0.93Mg0.07O2thin films show high (⩾80%) visible transmittance and sharp absorption at band gap energy with direct and indirect optical band gaps 3.11 and 2.58eV, respectively. Lower (∼450°C) substrate temperature formed films are amorphous and yield lower direct (2.96eV) and indirect (2.23eV) band gaps after crystallization. Electrical conductivity of CuCr0.93Mg0.07O2thin films ranged 0.6–1Scm−1and hole concentration ∼2×1019cm−3determined from Seebeck analysis. Temperature dependence of conductivity exhibit activation energies ∼0.11eV in 300–470K and ∼0.23eV in ⩾470K region ascribed to activated conduction and grain boundary trap assisted conduction, respectively. Heterojunction diodes of the structure Au/n-(ZnO)/p-(CuCr0.93Mg0.07O2)/SnO2(TCO) were fabricated which show potential for transparent wide band gap junction device.