Acquisition of Instrumentation for Full-spectrum Optically Detected Resonance Spectroscopy of Semiconductors

半导体量子阱（qw）、量子线和量子点目前引起了人们极大的兴趣，光学和红外（IR）技术对于理解这些低维半导体结构中的电子态、激发和相互作用至关重要。光学探测共振光谱（optical detection resonance， ODR）是一种结合了可见光/近红外光子探测和远红外激发的灵敏度的方法，它缓解了上述许多问题，最近得到了发展，并首次被共同研究人员扩展并用于研究掺杂量子阱中的中性和负供体离子以及量子阱中光生激子的内部跃迁。这些结果显示了ODR光谱在低维半导体结构研究中的应用前景。基于我们传统ODR方法的经验和我们最近借来的光谱仪/CCD阵列系统的演示实验，我们将获得一个高灵敏度，高分辨率的光谱仪/CCD阵列系统，并配备采集和分析软件，用于半导体纳米结构的全光谱ODR光谱研究。该系统将用于研究与高磁场下低维半导体结构的电子态有关的几个基本问题。该项目涉及两名高级研究人员的合作，他们的专业知识涵盖了从远红外到可见光的III-V和II-VI材料系统中的低维半导体结构的光学研究。研究的具体问题包括：带正电荷的激子和带负电荷的激子的内部态以及激子的回旋共振；多余电子和空穴对激子态和金属-绝缘体跃迁的影响整数和分数量子霍尔效应中的多体效应；以及ODR在量子线和量子点中杂质和自由载流子电子态研究中的应用。我们预计，该系统将大大提高这些实验的数量和质量，以及对学生的教育和培训。%%%***

9802875McCombeSemiconductor quantum wells (QWs), quantum wires and quantum dots are currently of great interest, and optical and infrared (IR) techniques have been central to developing an understanding of the electronic states, excitations and interactions in these low-dimensional semiconductor structures. Optically detected resonance (ODR) spectroscopy, an approach which combines the sensitivity of visible/near IR photon detection with far IR excitation, and which alleviates many of the problems alluded to above, has recently been developed, and extended and used for the first time by the co-investigators to study neutral and negative donor ions in doped QW's and internal transitions of photocreated excitons in QWs. These results demonstrate the promise of ODR spectroscopy for studies of low-dimensional semiconductor structures.Based on our experience with the conventional ODR approach and our recent demonstration experiments with a borrowed spectrograph/CCD array system, we will acquire a high sensitivity, high resolution mated spectrograph/CCD array system with acquisition and analysis software for full-spectrum ODR spectroscopy studies of semiconductor nanostructures. This system will be used to investigate several basic issues related to the electronic states of low-dimensional semiconductor structures in high magnetic fields. The project involves the collaboration of two senior investigators whose combined expertise spans optical studies of low-dimensional semiconductor structures in the III-V and II-VI materials systems from the far IR to the visible. Specific problems to be investigated include: internal states of negatively and positively charged excitons and cyclotron resonance of charged excitons; effects of excess electrons and holes on the excitonic states and the metal-insulator transition; many-body effects in the integer and fractional quantum Hall effect regimes; and application of ODR to the study of impurity and free carrier electronic states in quantum wires and quantum dots. We anticipate that the proposed system will greatly enhance both the quantity and quality of these experiments, and the education and training of our students.%%%***