Ryczko Krzysztof, Andrzejewski Janusz, Sęk Grzegorz
Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
Materials (Basel). 2021 Dec 22;15(1):60. doi: 10.3390/ma15010060.
In this study, we propose designs of an interband cascade laser (ICL) active region able to emit in the application-relevant mid infrared (MIR) spectral range and to be grown on an InP substrate. This is a long-sought solution as it promises a combination of ICL advantages with mature and cost-effective epitaxial technology of fabricating materials and devices with high structural and optical quality, when compared to standard approaches of growing ICLs on GaSb or InAs substrates. Therefore, we theoretically investigate a family of type II, "W"-shaped quantum wells made of InGaAs/InAs/GaAsSb with different barriers, for a range of compositions assuring the strain levels acceptable from the growth point of view. The calculated band structure within the 8-band k·p approximation showed that the inclusion of a thin InAs layer into such a type II system brings a useful additional tuning knob to tailor the electronic confined states, optical transitions' energy and their intensity. Eventually, it allows achieving the emission wavelengths from below 3 to at least 4.6 μm, while still keeping reasonably high gain when compared to the state-of-the-art ICLs. We demonstrate a good tunability of both the emission wavelength and the optical transitions' oscillator strength, which are competitive with other approaches in the MIR. This is an original solution which has not been demonstrated so far experimentally. Such InP-based interband cascade lasers are of crucial application importance, particularly for the optical gas sensing.
在本研究中，我们提出了一种带间级联激光器（ICL）有源区的设计，该有源区能够在与应用相关的中红外（MIR）光谱范围内发射，并能生长在InP衬底上。这是一个长期寻求的解决方案，因为与在GaSb或InAs衬底上生长ICL的标准方法相比，它有望将ICL的优势与成熟且具有成本效益的外延技术相结合，从而制造出具有高结构和光学质量的材料及器件。因此，我们从理论上研究了一族由InGaAs/InAs/GaAsSb制成、具有不同势垒的II型“W”形量子阱，研究范围涵盖了从生长角度确保应变水平可接受的一系列成分。在八能带k·p近似下计算得到的能带结构表明，在这样的II型系统中包含一层薄的InAs层，为定制电子受限态、光学跃迁能量及其强度带来了一个有用的额外调节旋钮。最终，它能够实现从低于3μm到至少4.6μm的发射波长，同时与最先进的ICL相比仍保持相当高的增益。我们展示了发射波长和光学跃迁振子强度的良好可调性，这与MIR中的其他方法具有竞争力。这是一种迄今尚未通过实验证明的原创解决方案。这种基于InP的带间级联激光器具有至关重要的应用价值，特别是在光学气体传感方面。
