Two-dimensional semiconductors exhibit pronounced many-body effects and intense optical responses due to strong Coulombic interactions. Consequently, subtle differences in photoexcitation conditions can strongly influence how the material dissipates energy during thermalization. Here, using multiple excitation spectroscopies, we show that a distinct thermalization pathway emerges at elevated excitation energies, enhancing the formation of trions and charged biexcitons in single-layer WSe₂ by up to 2× and 5× , respectively. Power- and temperature-dependent measurements lend insights into the origin of the enhancement. These observations underscore the complexity of excited state relaxation in monolayer semiconductors, provide insights for the continued development of carrier thermalization models, and highlight the potential to precisely control excitonic yields and probe nonequilibrium dynamics in 2D semiconductors.

中文翻译：

---

在单层 WSe2 中通过间隙以上激发增加三子和带电双激子的形成


由于强烈的库仑相互作用，二维半导体表现出明显的多体效应和强烈的光学响应。因此，光激发条件的细微差异会强烈影响材料在热化过程中的能量耗散方式。在这里，使用多重激发光谱，我们表明在激发能量升高时会出现独特的热化途径，将单层 WSe₂ 中 trions 和带电二激子的形成分别提高了 2× 和 5× 。与功率和温度相关的测量有助于深入了解增强功能的来源。这些观察结果强调了单层半导体中激发态弛豫的复杂性，为载流子热化模型的持续发展提供了见解，并强调了精确控制 2D 半导体中激子产率和探测非平衡动力学的潜力。