InAs/InGaAs heterostructures with quantum dots (QDs) have been studied for quite some time for light-emitting diodes operating from the near to the far infrared range. However, the room temperature QD emission is rather low, thus it is needed to look for improved structure designs allowing efficient enhancement of luminescence. In this work, we study the modification of photo- and thermo-electrical properties of InAs/In_0.15Ga_0.85As QD heterostructure, when introducing wide-bandgap In_0.15Al_0.85As confining barriers (CBs) at one or both sides of the QD layer. The structures demonstrate interband QD photoluminescence (PL) peaked at 1.2 μm measured from room temperature down to 10 K. The introduction of CBs allows to enhance the PL intensity by more than four orders of magnitude. The reason is a strong decrease of the thermal escape of both charge carriers confined in QDs and wetting layer, leading to a highly increased radiative recombination. The changes in optical transitions, involving quantum confinement states and defect-related levels, are studied by photocurrent (PC) measurements, also showing the expectable quenching of PC in the structures with CBs. The existing deep levels of defects are determined by thermally stimulated current spectroscopy. Having the same defect spectrum in all the studied structures, an increase in the defect density was detected near CBs at the QD layer. At low temperatures, defect traps in vicinity of the QDs layer caused the Coulomb screening of conductivity channel, that is studied by kinetics measurements in view of the CB introduction. The PC decrement under the constant illumination is theoretically explained by the screening. We confidently show that, despite of a slight increase in defects and PL blueshift in the QD structure with In_0.15Al_0.85As CBs, they can serve as improved active elements for energy-efficient QD lasers, single-photon emitters and optical amplifiers.

对于从近红外到远红外范围工作的发光二极管，已经研究了具有量子点（QD）的InAs / InGaAs异质结构。然而，室温QD发射相当低，因此需要寻找允许有效增强发光的改进的结构设计。在这项工作中，当引入宽带隙In _0.15 Al _0.85时，我们研究了InAs / In _0.15 Ga _0.85 As QD异质结构的光电性能的改变作为QD层一侧或两侧的限制屏障（CB）。该结构表明带间QD光致发光（PL）在室温至10 K范围内达到1.2μm的峰值。CB的引入使PL强度提高了四个数量级以上。原因是限制在量子点和润湿层中的两个载流子的热逸出大大减少，从而导致辐射复合高度增加。通过光电流（PC）测量研究了涉及量子限制状态和缺陷相关能级的光学跃迁的变化，还显示了在CBs结构中PC的预期淬灭。现有的深层缺陷水平是通过热激发电流光谱法确定的。在所有研究的结构中具有相同的缺陷谱，在QD层的CB附近检测到缺陷密度的增加。在低温下，QDs层附近的缺陷陷阱导致了电导率通道的库仑筛选，考虑到CB的引入，通过动力学测量对其进行了研究。理论上通过屏蔽可以解释恒定照明下PC的减量。我们有信心地表明，尽管使用In的QD结构中缺陷和PL蓝移略有增加，_0.15 Al _0.85作为CB，它们可以用作节能型QD激光器，单光子发射器和光放大器的改进有源元件。