Probing dopant incorporation in InAs/GaAs QDIPs by polarization-dependent Fourier transform infrared spectroscopy

• Published in: Infrared physics & technology Vol. 51; no. 2; pp. 131 - 135
• Main Authors: Zhao, Z.Y., Yi, C., Stiff-Roberts, A.D., Hoffman, A.J., Wasserman, D., Gmachl, C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-10-2007; Elsevier
• Subjects: Applied sciences; Astronomy; Bolometer; infrared, submillimeter wave, microwave and radiowave receivers and detectors; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Deep-level defect center; Doping; Earth, ocean, space; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronics; Exact sciences and technology; Fourier transform infrared spectroscopy; Fundamental astronomy and astrophysics. Instrumentation, techniques, and astronomical observations; Historical astronomy and archaeoastronomy; and other topics in fundamental astronomy and astrophysics; instrumentation, techniques, and astronomical observations; Infrared, submillimeter wave, microwave and radiowave instruments, equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Optoelectronic devices; Physics; Polarization-dependent absorbance spectrum; Quantum dots; Quantum-dot infrared photodetector; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Deep-level defect center; 73.21.La; 74.62.Dh; Polarization-dependent absorbance spectrum; Doping; 78.30.−j; Fourier transform infrared spectroscopy; Quantum-dot infrared photodetector; 78.67.−n; Quantum dot; Fourier transformation; Infrared detector; 73.21.La; 78.67.-n; 78.30.-j; 74.62.Dh; Energy level; Photodetector; Gallium Arsenides; Radiation detector; Quantum dot devices; Indium Arsenides; Quantum-dot infrared photodetector; Fourier transform infrared spectroscopy; Polarization-dependent absorbance spectrum; Deep-level defect center; Doping; Heterostructures; Deep level
• ISSN: 1350-4495; 1879-0275
• DOI: 10.1016/j.infrared.2007.04.002

In order to improve spectral response tunability of quantum-dot infrared photodetectors (QDIPs), it is critical to understand how dopants are incorporated into quantum dots (QDs). In this letter, polarization-dependent Fourier transform infrared spectroscopy is used to measure intraband absorption in InAs/GaAs QDs. Through the investigation of device heterostructures with varying modulation-doped carrier concentrations, we have correlated the charge filling process of energy levels in high-density QD ensembles with IR absorbance spectra. In addition, we have observed the IR signature of a transition originating in deep-level defect centers arising from Si-doped GaAs.