Cobalt selenide thin films were prepared onto tin oxide-coated glass substrates by electrodeposition method.The electrochemical mechanisms for this thin film formation were investigated by cyclic voltammetry (CV), and the results show that cobalt selenide compound phases are formed via either surface induced reduction by predeposited selenium or directly reaction with H2Se from six electron reduction of H2SeO3.It is also found that films' stoichiometry and morphology are significantly influenced by deposition potential, deposition temperature and pH value.Se-rich CoSe thin films with hexagonal crystal structure and compact morphology can be obtained at deposition potential of -0.5V (vs SCE), deposition temperature of 50℃ and pH value of 2.0.The electrodeposited CoSe film shows an optical absorption coefficient of higher than 1 × 105 cm-1, and an optical band gap of (1.53±0.01) eV which is close to the theoretical optimization value of the light absorption layer materials in single-junction solar cell.%采用电沉积方法在SnO2玻璃基底上制备了Co-Se化合物薄膜.研究了薄膜形成的电化学机理和电沉积工艺对薄膜组成与形貌的影响,并表征了薄膜的结构与光学性质.结果表明:Co2+受预沉积Se的表面诱导还原或直接与H2SeO3的六电子还原反应产物H2Se发生反应形成Co-Se化合物;沉积电位、沉积温度和pH值均显著影响电沉积Co-Se化合物薄膜的形貌与成分;在沉积电位为-0.5V(vs SCE)、沉积温度为50℃和pH值为2.0时可制备出表面致密平格且呈六方晶型结构的富硒CoSe薄膜,其光吸收系数达到1×105 cm-1,直接带隙宽度为(1.53±0.01)eV,接近单结太阳电池光吸收层材料的理论最佳值.
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