Characterization and Photocurrent Spectroscopy of Single Quantum Wells

C. A. Parsons; B. R. Thacker; D. M. Szmyd; M. W. Peterson; W. E. McMahon; A. J. Nozik

doi:10.1063/1.459350

Characterization and Photocurrent Spectroscopy of Single Quantum Wells

C. A. Parsons, B. R. Thacker, D. M. Szmyd, M. W. Peterson, W. E. McMahon, A. J. Nozik

Chemistry and Nanoscience

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Abstract

GaAs/Al_xGa_1-xAs single quantum wells (SQWs) have been characterized by various spectroscopies and studied as electrodes in photoelectrochemical cells and in gold Schottky barrier structures. The techniques used were photoreflectance (PR), photoluminescence (PL), photocurrent (PC) spectroscopy, and impedance measurements. The energy level structure and well shape were best determined from PR data. The p doping of the buffer layer eliminated p-n junctions between the buffer layer and substrate and the inner Al_xGa_1-x(As barrier, thereby producing nearly ideal Mott-Schottky plots (no frequency dispersion or light dependence) so that the flatband potentials of these SQW electrodes could be well determined. Stark shifts in the PC spectra could also be seen if the buffer layer of the electrodes is doped p type. Very high quantum yields exhibited by SQW electrodes at room temperature with thick (270 Å) Al_xGa_1-xAs barriers are explained by thermionic emission. At low temperatures with Schottky barriers, other mechanisms, such as tunneling, dominate. Hot photoluminescence spectra were also obtained and the hot carrier behavior of SQWs is compared with multiple quantum wells.

Original language	American English
Pages (from-to)	7706-7715
Number of pages	10
Journal	The Journal of Chemical Physics
Volume	93
Issue number	11
DOIs	https://doi.org/10.1063/1.459350 https://doi.org/10.1063/1.459350
State	Published - 1990

NREL Publication Number

ACNR/JA-236-11849

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@article{02d2fdd3e0c74ed5b00e57d0dd1ac239,

title = "Characterization and Photocurrent Spectroscopy of Single Quantum Wells",

abstract = "GaAs/AlxGa1-xAs single quantum wells (SQWs) have been characterized by various spectroscopies and studied as electrodes in photoelectrochemical cells and in gold Schottky barrier structures. The techniques used were photoreflectance (PR), photoluminescence (PL), photocurrent (PC) spectroscopy, and impedance measurements. The energy level structure and well shape were best determined from PR data. The p doping of the buffer layer eliminated p-n junctions between the buffer layer and substrate and the inner AlxGa1-x(As barrier, thereby producing nearly ideal Mott-Schottky plots (no frequency dispersion or light dependence) so that the flatband potentials of these SQW electrodes could be well determined. Stark shifts in the PC spectra could also be seen if the buffer layer of the electrodes is doped p type. Very high quantum yields exhibited by SQW electrodes at room temperature with thick (270 {\AA}) AlxGa1-xAs barriers are explained by thermionic emission. At low temperatures with Schottky barriers, other mechanisms, such as tunneling, dominate. Hot photoluminescence spectra were also obtained and the hot carrier behavior of SQWs is compared with multiple quantum wells.",

author = "Parsons, {C. A.} and Thacker, {B. R.} and Szmyd, {D. M.} and Peterson, {M. W.} and McMahon, {W. E.} and Nozik, {A. J.}",

year = "1990",

doi = "10.1063/1.459350",

language = "American English",

volume = "93",

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journal = "The Journal of Chemical Physics",

issn = "0021-9606",

publisher = "American Institute of Physics",

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T1 - Characterization and Photocurrent Spectroscopy of Single Quantum Wells

AU - Parsons, C. A.

AU - Thacker, B. R.

AU - Szmyd, D. M.

AU - Peterson, M. W.

AU - McMahon, W. E.

AU - Nozik, A. J.

PY - 1990

Y1 - 1990

N2 - GaAs/AlxGa1-xAs single quantum wells (SQWs) have been characterized by various spectroscopies and studied as electrodes in photoelectrochemical cells and in gold Schottky barrier structures. The techniques used were photoreflectance (PR), photoluminescence (PL), photocurrent (PC) spectroscopy, and impedance measurements. The energy level structure and well shape were best determined from PR data. The p doping of the buffer layer eliminated p-n junctions between the buffer layer and substrate and the inner AlxGa1-x(As barrier, thereby producing nearly ideal Mott-Schottky plots (no frequency dispersion or light dependence) so that the flatband potentials of these SQW electrodes could be well determined. Stark shifts in the PC spectra could also be seen if the buffer layer of the electrodes is doped p type. Very high quantum yields exhibited by SQW electrodes at room temperature with thick (270 Å) AlxGa1-xAs barriers are explained by thermionic emission. At low temperatures with Schottky barriers, other mechanisms, such as tunneling, dominate. Hot photoluminescence spectra were also obtained and the hot carrier behavior of SQWs is compared with multiple quantum wells.

AB - GaAs/AlxGa1-xAs single quantum wells (SQWs) have been characterized by various spectroscopies and studied as electrodes in photoelectrochemical cells and in gold Schottky barrier structures. The techniques used were photoreflectance (PR), photoluminescence (PL), photocurrent (PC) spectroscopy, and impedance measurements. The energy level structure and well shape were best determined from PR data. The p doping of the buffer layer eliminated p-n junctions between the buffer layer and substrate and the inner AlxGa1-x(As barrier, thereby producing nearly ideal Mott-Schottky plots (no frequency dispersion or light dependence) so that the flatband potentials of these SQW electrodes could be well determined. Stark shifts in the PC spectra could also be seen if the buffer layer of the electrodes is doped p type. Very high quantum yields exhibited by SQW electrodes at room temperature with thick (270 Å) AlxGa1-xAs barriers are explained by thermionic emission. At low temperatures with Schottky barriers, other mechanisms, such as tunneling, dominate. Hot photoluminescence spectra were also obtained and the hot carrier behavior of SQWs is compared with multiple quantum wells.

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DO - 10.1063/1.459350

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SN - 0021-9606

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EP - 7715

JO - The Journal of Chemical Physics

JF - The Journal of Chemical Physics

IS - 11

ER -

Characterization and Photocurrent Spectroscopy of Single Quantum Wells

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