发表机构
Faculty of Philosophy, University of East Sarajevo; Faculty of Physics, University of Belgrade; Vinca Institute of Nuclear Sciences—National Institute of the Republic of Serbia, University of Belgrade（东萨拉热窝大学哲学系; 贝尔格莱德大学物理系; 塞尔维亚共和国国家研究所文查核科学研究所，贝尔格莱德大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文建立理论模型，分析光生载流子扩散与复合对不透明半导体光热响应的影响，发现即使表面复合为零且寿命短，载流子热贡献仍存在，为光热实验设计和电子特性表征提供指导。
AI 中文摘要
由于激光辐射的吸收，半导体的光热响应同时受晶格热化和光生载流子动力学的影响。这种与载流子相关的贡献通过载流子扩散和复合在温度场中留下特征印记，使得光热响应对电子输运和复合特性敏感。这种敏感性为利用光热方法表征半导体的电子特性提供了基础。在本文中，我们建立了一个理论模型，用于描述在谐波调制激光激发下中等掺杂的不透明半导体的光热响应，该模型考虑了少数载流子的产生、扩散和复合。我们分析了载流子寿命、扩散长度和表面复合速度如何影响由此产生的温度场，进而影响光热信号。特别地，我们表明，即使表面复合速率消失且载流子寿命较短，与载流子复合相关的热贡献仍然非零，这证明在可能预期其贡献变得可忽略的条件下，光生载流子的印记仍可能持续存在。这些结果为光热和光声实验的设计和解释提供了指导，包括调制频率和检测几何结构的选择，以增强对载流子相关热印记的敏感性，并改进半导体材料和器件电子特性的测定。
英文摘要
As a consequence of laser radiation absorption, the photothermal response of semiconductors is governed by both the thermalization of the crystal lattice and the dynamics of photogenerated charge carriers. This carrier-related contribution leaves a characteristic signature in the temperature field through carrier diffusion and recombination, making the photothermal response sensitive to electronic transport and recombination properties. This sensitivity provides the basis for using photothermal methods to characterize the electronic properties of semiconductors. In this paper, we develop a theoretical model of the photothermal response of moderately doped opaque semiconductors under harmonically modulated laser excitation, accounting for the generation, diffusion, and recombination of minority charge carriers. We analyze how carrier lifetime, diffusion length, and surface recombination velocity affect the resulting temperature field and, consequently, the photothermal signal. In particular, we show that the thermal contribution associated with carrier recombination remains nonzero even when the surface recombination rate vanishes and for short carrier lifetimes, demonstrating that the signature of photogenerated carriers may persist under conditions where their contribution might otherwise be expected to become negligible. The results provide guidance for both the design and interpretation of photothermal and photoacoustic experiments, including the choice of modulation frequency and detection geometry, to enhance the sensitivity to carrier-related thermal signatures and improve the determination of electronic properties of semiconductor materials and devices.
Comments20 pages, 6 figures
