CdS/CdTe多晶薄膜的时间光谱特性

采用超短皮秒脉冲激光激发制备了SnO₂:F 玻璃衬底和石英衬底的CdTe多晶薄膜,在室温下测量其稳态和瞬态荧光光谱。结果表明,随着激发功率的增大,其荧光光谱峰逐渐展宽,并发生蓝移。对于退火处理的样品,其荧光光谱伴随主峰旁出现一个肩峰,是Cl 原子与富Cd区存在的空位形成复合体引起的发射。其瞬态荧光光谱寿命呈双指数衰减,即表面效应所引起的慢过程和带边激子态发射的快过程组成。样品退火处理后荧光寿命变长,有利于电子-空穴对在复合发光前分离,提高电子空穴的迁移率,改善其光伏性能。

Time-resolved Photoluminescence Studies of Polycrystalline CdS/CdTe

In this work,the steady-state photoluminescence(PL) and time-resolved photoluminescence(TRPL) of polycrystalline CdTe on different substrates were measured at room temperature by a Nd∶YAG picosecond laser as the excitation source.With the increasing of pump power,the PL spectra have been broadened towards high photon energy.The PL spectra of the annealed sample exhibit another small band,which is attributed to the donor-acceptor pair recombination by a chlorine donor and a cadmium vacancy complex acceptor.The PL decay curve presents bi-exponential processes.The processes with long and short lifetimes are related to surface trapping state and band-edge excitonic state,respectively.Annealing treatment makes the fluorescence lifetime longer and benefits for the separation of the electron-hole pair before being composited.