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Infrared Absorption Efficiency in AlAs/Al x Ga 1–x As Type‐II Multiple‐Quantum‐Well, Structure Grown on (211) GaAs Substrate
Author(s) -
Zhu QinSheng,
He Y.P.,
Zhong Z.T.,
Sun X.H.,
Hiramatsu K.
Publication year - 2000
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(200002)217:2<833::aid-pssb833>3.0.co;2-l
Subject(s) - quantum efficiency , infrared , molecular beam epitaxy , quantum well , ground state , excited state , materials science , absorption (acoustics) , substrate (aquarium) , optoelectronics , perpendicular , effective mass (spring–mass system) , absorption spectroscopy , analytical chemistry (journal) , chemistry , optics , epitaxy , atomic physics , physics , nanotechnology , geometry , mathematics , quantum mechanics , geology , composite material , laser , oceanography , layer (electronics) , chromatography
We have made a normal incidence high infrared absorption efficiency AlAs/Al 0.55 Ga 0.45 As multiple‐quantum‐well structure grown on (211) GaAs substrates by molecular beam epitaxy (MBE). A strong infrared absorption signal at 11.6 μm due to the transition of the ground state to the first excited state, and a small signal at 6.8 μm due to the transition from the ground state to continuum, were observed. A 45° tilted incidence measurement was also performed on the same sample for the comparison with a normal incidence measurement. Both measurements provide important information about the quantum well absorption efficiency. Efficiencies which evaluate the absorption of electric components perpendicular and parallel to the well plane are η ⊥ = 25% and η ∥ = 88%, respectively. The total efficiency is then deduced to be η ⊥ = 91%. It is apparent that the efficiency η ∥ dominates the total quantum efficiency η . Because an electron in the (211) AlAs well has a small effective mass ( m * zx or m * zy ), the normal incidence absorption coefficient is expected to be higher than that grown on (511) and (311) substrates. Thus, in the present study, we use the (211) substrate to fabricate QWIP. The experimental results indicate the potential of these novel structures for use as normal incidence infrared photodetectors.