Photoluminescence determination of the binding energy of residual donors in 300-Å GaAs/AlxGa1xAs quantum wells

D. C. Reynolds, K. R. Evans, C. E. Stutz, K. K. Bajaj, and P. W. Yu
Phys. Rev. B 44, 8869 – Published 15 October 1991
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Abstract

The binding energy EB of residual donors in nominally 300-Å-wide GaAs/AlxGa1xAs quantum wells has been determined from the results of low-temperature photoluminescence (PL), PL-excitation (PLE), and resonant-excitation (RE) measurements. The center of each quantum well was δ doped with 3×109 cm2 Be acceptors, resulting in ionization of residual donors and allowing the observation of free-heavy-hole-to-donor (D0,h) transitions. The n=1 (D0,h), transition for center-well donors was observed in PL, and the n=2 (D0,h) transition for center-well donors was observed in PLE. Two transitions associated with (D0,h) were observed in PLE; it is proposed that both the 2s and 2p± excited states of the donor are being observed. The calculated binding energy of the 2s and 2p± excited states can be added to the measured transition energy from the heavy-hole subband to the respective excited states. This method gives a donor binding energy of 8.0±0.5 meV. The calculated binding energy of the donor for a 300-Å-wide well is 8.7 meV according to Greene and Bajaj. The observed energy separation between the 2s and 2p± excited states of the donor is 0.7 meV, in reasonably good agreement with the calculated value of 0.5 meV. We note that this work is an observation of the n=2 state of the donor from PLE spectra, as well as the detection of the 2s and 2p± levels.

  • Received 8 April 1991

DOI:https://doi.org/10.1103/PhysRevB.44.8869

©1991 American Physical Society

Authors & Affiliations

D. C. Reynolds

  • Southeastern Center for Electrical Engineering Education, St. Cloud, Florida 32769

K. R. Evans and C. E. Stutz

  • Wright Laboratory, Electronic Technology Directorate (WL/ELRA), Wright-Patterson Air Force Base, Ohio 45433-6543

K. K. Bajaj

  • Physics Department, Emory University, Atlanta, Georgia 30322

P. W. Yu

  • University Research Center, Wright State University, Dayton, Ohio 45435

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Vol. 44, Iss. 16 — 15 October 1991

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