Characterization of liquid phase epitaxial GaAs for blocked-impurity-band far-infrared detectors

• Published in: Infrared physics & technology 2005-06, Vol.46 (5), p.400-407
• Main Authors: Cardozo, B.L., Reichertz, L.A., Beeman, J.W., Haller, E.E.
• Format: Article
• Language: English
• Subjects: Applied sciences; BIB; Bolometer; infrared, submillimeter wave, microwave and radiowave receivers and detectors; Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Far-infrared detectors; Gallium arsenide; Infrared, submillimeter wave, microwave and radiowave instruments, equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); LPE; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optoelectronic devices; Photodetectors (including infrared and CCD detectors); Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 1350-4495; 1879-0275
• DOI: 10.1016/j.infrared.2004.07.002

GaAs blocked-impurity-band (BIB) photoconductor detectors have the potential to become the most sensitive, low noise detectors in the far-infrared below 45.5cm−1 (⩾220μm). We have studied the characteristics of liquid phase epitaxial GaAs films relevant to BIB detector production, including impurity band formation and the infrared absorption of the active section of the device. Knowledge of the far-infrared absorption spectrum as a function of donor concentration combined with variable temperature Hall effect and resistivity studies leads us to conclude that the optimal concentration for the absorbing layer of a GaAs BIB detector lies between 1×1015 and 6.7×1015cm−3. At these concentrations there is significant wave function overlap which in turn leads to absorption beyond the 1s ground to 2p bound excited state transition of 35.5cm−1 (282μm). There still remains a gap between the upper edge of the donor band and the bottom of the conduction band, a necessity for proper BIB detector operation.