A detailed analysis of the electrical response of In_0.3Ga_0.7As surface quantum dots (SQDs) coupled to 5-layer buried quantum dots (BQDs) is carried out as a function of ethanol and acetone concentration while temperature-dependent photoluminescence (PL) spectra are also analyzed. The coupling structure is grown by solid source molecular beam epitaxy. Carrier transport from BQDs to SQDs is confirmed by the temperature-dependent PL spectra. The importance of the surface states for the sensing application is once more highlighted. The results show that not only the exposure to the target gas but also the illumination affect the electrical response of the coupling sample strongly. In the ethanol atmosphere and under the illumination, the sheet resistance of the coupling structure decays by 50% while it remains nearly constant for the reference structure with only the 5-layer BQDs but not the SQDs. The strong dependence of the electrical response on the gas concentration makes SQDs very suitable for the development of integrated micrometer-sized gas sensor devices.

中文翻译：

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In 0.3 Ga 0.7 As表面量子点与多层掩埋量子点的气敏性

In _0.3 Ga _0.7的电响应的详细分析由于耦合到5层掩埋量子点（BQDs）的表面量子点（SQDs）是乙醇和丙酮浓度的函数，同时还分析了随温度变化的光致发光（PL）光谱。耦合结构通过固体源分子束外延生长。从BQD到SQD的载流子传输通过与温度有关的PL光谱得以确认。表面状态对于传感应用的重要性再次得到强调。结果表明，不仅暴露于目标气体，而且光照也强烈影响偶联样品的电响应。在乙醇气氛中和光照下，耦合结构的薄层电阻衰减50％，而对于只有5层BQD而不是SQD的参考结构，其薄层电阻几乎保持恒定。