Low Temperature Photoluminescence and Carrier Relaxation Dynamics of GaAs Defect States

本研究是基于光致发光(Photoluminescence, PL)和瞬态反射(Transiet Reflection, TR)两种光谱技术，系统研究了GaAs晶体内部原生缺陷的类型及其对载流子动力学行为的影响机制。通过低温77 K下的PL光谱。识别出位于851 nm (GaAs)和924 nm ( Ga AS 2− )处的两个反位点缺陷特征发光峰，研究其并构建了相关的光学跃迁模型。进一步利用瞬态反射光谱研究了光激发下GaAs的超快载流子动力学行为。通过室温与低温实验对比，发现缺陷态会对光生载流子起到非辐射复合的作用，极大地改变了载流子的弛豫过程且缩短其寿命，并建立载流子弛豫路径的相应理论模型。该研究结果为揭示GaAs晶体缺陷发光机制以及载流子调控提供了实验依据，有助于深入理解半导体材料内部缺陷对器件性能和寿命的影响。This study offers a comprehensive exploration of primary defects in GaAs crystals and their impact on carrier dynamics, employing Photoluminescence (PL) and Transient Reflection (TR) spectroscopy. At 77 K, PL spectroscopy reveals two antisite defect luminescence peaks at 851 nm (GaAs) and 924 nm ( Ga AS 2− ), with related optical transition models established. Transient reflection spectroscopy further examines GaAs carrier dynamics post-photoexcitation. Comparing room-temperature and 77 K experiments shows defect states act as non-radiative recombination centers for photogenerated carriers, altering carrier relaxation and reducing lifetimes. A theoretical model of carrier relaxation pathways is also presented. These results elucidate GaAs defect luminescence mechanisms and carrier regulation, enhancing understanding of how semiconductor material defects affect device performance and longevity.