High-performance III–V quantum-dot lasers monolithically grown on Si substrates have been demonstrated as a promising solution to realize Si-based laser sources with very low threshold current density, high output power, and long lifetime, even with relatively high density of defects due to the material dissimilarities between III–Vs and Si. On the other hand, although conventional III–V quantum-well lasers grown on Si have been demonstrated after great efforts worldwide for more than 40 years, their practicality is still a great challenge because of their very high threshold current density and very short lifetime. However, the physical mechanisms behind the superior performance of silicon-based III–V quantum-dot lasers remain unclear. In this paper, we directly compare the performance of a quantum-well and a quantum-dot laser monolithically grown on on-axis Si (001) substrates, both experimentally and theoretically, under the impact of the same density of threading dislocations. A quantum-dot laser grown on a Si substrate with a high operating temperature (105 °C) has been demonstrated with a low threshold current density of 173 A/cm2 and a high single facet output power >100 mW at room temperature, while there is no lasing operation for the quantum-well device at room temperature even at high injection levels. By using a rate equation travelling-wave model, the quantum-dot laser's superior performance compared with its quantum well-based counterpart on Si is theoretically explained in terms of the unique properties of quantum dots, i.e., efficient carrier capture and high thermal energy barriers preventing the carriers from migrating into defect states.

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在硅上生长的 InAs/GaAs 量子点激光器的缺陷容限起源

在 Si 衬底上单片生长的高性能 III-V 量子点激光器已被证明是实现具有非常低阈值电流密度、高输出功率和长寿命的 Si 基激光源的有前途的解决方案，即使具有相对较高的密度由于 III-Vs 和 Si 之间的材料不同而导致的缺陷。另一方面，尽管在全球范围内经过 40 多年的努力，在硅上生长的常规 III-V 族量子阱激光器已经得到证明，但由于其非常高的阈值电流密度和非常短的寿命，它们的实用性仍然是一个巨大的挑战。然而，硅基 III-V 量子点激光器优异性能背后的物理机制仍不清楚。在本文中，在相同密度的穿透位错的影响下，我们在实验和理论上直接比较了在轴上 Si (001) 衬底上单片生长的量子阱和量子点激光器的性能。在高工作温度 (105 °C) 的硅衬底上生长的量子点激光器已被证明具有 173 A/cm2 的低阈值电流密度和室温下 >100 mW 的高单面输出功率，而即使在高注入水平下，量子阱器件在室温下也没有激光操作。通过使用速率方程行波模型，量子点激光器与基于量子阱的 Si 激光器相比的优越性能从理论上解释为量子点的独特性质，即：