In this work, we briefly review the development and status of interband cascade lasers (ICLs) as related to long-standing issues due to the InAs/AlSb superlattice cladding. By focusing on a hybrid cladding approach to alleviate these issues, we demonstrate substantially improved device performance of ICLs compared to earlier reported ICLs of a similar design in the 3–4 µm wavelength region. These improvements include a threshold current density for broad-area devices as low as 134 A/cm² at 300 K and reduced threshold voltage with a peak voltage efficiency of 80%, which is more than 10% higher than that obtained from previously reported ICLs. Moreover, we have demonstrated continuous wave (cw) operation of a broad-area device up to 278 K, the highest cw operating temperature among epi-side up mounted broad-area type-II ICLs, implying improved thermal dissipation with the hybrid cladding approach. Additionally, by conducting a comparative study of ICLs with different GaSb layer thicknesses in the hole injector, we reveal and discuss an interesting correlation between the carrier transport, threshold voltage, and hole-induced absorption loss, which may help to guide device optimization for operation in a targeted temperature range.

在这项工作中，我们简要回顾了带间级联激光器 (ICL) 的发展和现状，以及与 InAs/AlSb 超晶格包层导致的长期存在的问题相关的问题。通过专注于混合包层方法来缓解这些问题，我们证明了与早期报道的类似设计的 ICL 在 3-4 µm 波长区域相比，ICL 的器件性能得到了显着改善。这些改进包括大面积器件在 300 K 下的阈值电流密度低至 134 A/cm ²以及降低的阈值电压，峰值电压效率为 80%，比之前报道的 ICL 获得的效率高出 10% 以上。此外，我们还展示了大面积器件的连续波 (cw) 工作温度高达 278 K，这是外延面朝上安装的大面积 II 型 ICL 中最高的连续波工作温度，这意味着混合包层方法可以改善散热。此外，通过对空穴注入器中具有不同 GaSb 层厚度的 ICL 进行比较研究，我们揭示并讨论了载流子传输、阈值电压和空穴引起的吸收损耗之间的有趣相关性，这可能有助于指导器件运行优化在目标温度范围内。