TY - JOUR
T1 - DX -like centers in InAsGaAs QDIPs observed by polarization-dependent Fourier transform infrared spectroscopy
AU - Zhao, Z. Y.
AU - Yi, C.
AU - Stiff-Roberts, A. D.
AU - Hoffman, A. J.
AU - Wasserman, D.
AU - Gmachl, C.
N1 - Funding Information:
One of the authors (A.D.S.-R.) acknowledges support by the National Science Foundation under Grant No. 0547273 and the Air Force Office of Scientific Research under Grant No. FA9550-06-1-0482. Another two authors (A.D.S.-R. and Z.Y.Z.) acknowledge the Duke University Graduate School and Nanoscience Program (GPNANO Fellowship). Other author (A.J.H.) acknowledges support from PRISM, Princeton. Another author (D.W.) acknowledges support from the Princeton Council on Science and Technology.
PY - 2007
Y1 - 2007
N2 - In order to decrease dark current density and improve spectral response tunability of quantum dot infrared photodetectors (QDIPs), it is critical to understand how dopants are incorporated into quantum dot active regions. In this article, polarization-dependent Fourier transform infrared absorbance spectroscopy is used to measure intraband absorption in InAsGaAs QDIP heterostructures featuring different molecular beam epitaxy remote doping schemes. In addition to a QD absorbance peak near 90 meV, a peak at 405 meV is observed. This peak at 405 meV demonstrates signature characteristics of DX centers in III-V semiconductors, such as spherical symmetry, thermal activation of trapped carriers with increasing temperature, and dependence of absorbance peak magnitude (and thereby DX center concentration) on doping concentration and doping scheme. A conduction band energy diagram for the observed DX -like center and the corresponding optical ionization process is proposed. In addition, the effect of these DX -like centers on measured dark current density at T=50 K of the corresponding fabricated QDIPs is discussed.
AB - In order to decrease dark current density and improve spectral response tunability of quantum dot infrared photodetectors (QDIPs), it is critical to understand how dopants are incorporated into quantum dot active regions. In this article, polarization-dependent Fourier transform infrared absorbance spectroscopy is used to measure intraband absorption in InAsGaAs QDIP heterostructures featuring different molecular beam epitaxy remote doping schemes. In addition to a QD absorbance peak near 90 meV, a peak at 405 meV is observed. This peak at 405 meV demonstrates signature characteristics of DX centers in III-V semiconductors, such as spherical symmetry, thermal activation of trapped carriers with increasing temperature, and dependence of absorbance peak magnitude (and thereby DX center concentration) on doping concentration and doping scheme. A conduction band energy diagram for the observed DX -like center and the corresponding optical ionization process is proposed. In addition, the effect of these DX -like centers on measured dark current density at T=50 K of the corresponding fabricated QDIPs is discussed.
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U2 - 10.1116/1.2484803
DO - 10.1116/1.2484803
M3 - Article
AN - SCOPUS:34249889964
VL - 25
SP - 1108
EP - 1112
JO - Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
JF - Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
SN - 0734-211X
IS - 3
ER -