Photoluminescence properties of ZnS epilayers
Photoluminescence properties of ZnS epilayers
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DOI：
10.1063/1.363937
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发表时间：
1997-03-15
影响因子：
3.2
通讯作者：
Summers, CJ
中科院分区：
文献类型：
--
作者：
Tran, TK;Park, W;Summers, CJ
本文报道了用金属有机分子束外延和化学束外延在GaAs衬底上生长的ZnS薄膜在1.6 ~ 320 K之间的光致发光特性的综合研究。在低温下观察到重空穴和轻空穴自由激子，线宽分别为7.0和5.3 meV，以及施主和受主束缚激子和自由束缚复合沿着与它们的纵向光学（LO）声子副本。自由激子发射被观察到高达320 K，并使室温下的ZnS的带隙被明确地确定为3.723 eV。的峰位，强度和线宽的温度依赖性很好地描述了传统的经验关系和Toyozawa的激子线形理论。束缚激子峰的位置被发现遵循的带隙的温度依赖性，而自由-束缚复合功能的位移由（1/2）kT以上的带隙能量。施主束缚激子的热猝灭由一步猝灭过程描述，活化能为14.4 meV。在2.846 eV处还观察到自激活（SA）中心，线宽为410 meV。用组态坐标模型很好地描述了SA发射的温度依赖性。从热增宽的SA发射，平均声子能量为47.5毫电子伏，确定在良好的协议与LO声子能量。(C)1997年美国物理学会。
A comprehensive study is reported of the photoluminescence properties of ZnS thin films between 1.6 and 320 K grown by metalorganic molecular beam epitaxy and chemical beam epitaxy on GaAs substrates. Both heavy- and light-hole free excitons were observed at low temperatures with linewidths of 7.0 and 5.3 meV, respectively, as well as donor- and acceptor-bound excitons and free-to-bound recombination along with their longitudinal optical (LO) phonon replicas. The free exciton emission was observed up to 320 K, and enabled the room temperature band gap of ZnS to be unambiguously determined as 3.723 eV. The temperature dependence of the peak position, intensity, and linewidth was well described by the conventional empirical relations and by Toyozawa's exciton line shape theory. The bound exciton peak positions were found to follow the temperature dependence of the band gap whereas the free-to-bound recombination feature was displaced by (1/2)kT above the band gap energy. Thermal quenching of the donor-bound exciton was described by a one-step quenching process with an activation energy of 14.4 meV. The self-activation (SA) center was also observed at 2.846 eV with a linewidth of 410 meV. The temperature dependence of the SA emission was well described by the configuration coordinate model. From the thermal broadening of the SA emission, an average phonon energy of 47.5 meV was determined in good agreement with the LO phonon energy. (C) 1997 American Institute of Physics.