Secondary electron emission contrast of quantum wells in GaAs p-i-n junctions

Enrique Grunbaum; Zahava Barkay; Yoram Shapira; Keith W.J. Barnham; David B. Bushnell; Nicholas J. Ekins-Daukes; Massimo Mazzer; Peter Wilshaw

doi:10.1017/S1431927609090205

Secondary electron emission contrast of quantum wells in GaAs p-i-n junctions

Enrique Grunbaum^*, Zahava Barkay, Yoram Shapira, Keith W.J. Barnham, David B. Bushnell, Nicholas J. Ekins-Daukes, Massimo Mazzer, Peter Wilshaw

^*Corresponding author for this work

Department of Electrical Engineering - Physical Eng.

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

The secondary electron (SE) signal over a cleaved surface of GaAs p-i-n solar cells containing stacks of quantum wells (QWs) is analyzed by high-resolution scanning electron microscopy. The InGaAs QWs appear darker than the GaAsP barriers, which is attributed to the differences in electron affinity. This method is shown to be a powerful tool for profiling the conduction band minimum across junctions and interfaces with nanometer resolution. The intrinsic region is shown to be pinned to the Fermi level. Additional SE contrast mechanisms are discussed in relation to the dopant regions themselves as well as the AlGaAs window at the p-region. A novel method of in situ observation of the SE profile changes resulting from reverse biasing these structures shows that the built-in potential may be deduced. The obtained value of 0.7 eV is lower than the conventional bulk value due to surface effects.

Original language	English
Pages (from-to)	125-129
Number of pages	5
Journal	Microscopy and Microanalysis
Volume	15
Issue number	2
DOIs	https://doi.org/10.1017/S1431927609090205
State	Published - Apr 2009

Keywords

Conductance band
Dopant contrast
GaAs
High-resolution scanning electron microscopy
Quantum wells
Secondary electrons
Valence band

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1017/S1431927609090205

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title = "Secondary electron emission contrast of quantum wells in GaAs p-i-n junctions",

abstract = "The secondary electron (SE) signal over a cleaved surface of GaAs p-i-n solar cells containing stacks of quantum wells (QWs) is analyzed by high-resolution scanning electron microscopy. The InGaAs QWs appear darker than the GaAsP barriers, which is attributed to the differences in electron affinity. This method is shown to be a powerful tool for profiling the conduction band minimum across junctions and interfaces with nanometer resolution. The intrinsic region is shown to be pinned to the Fermi level. Additional SE contrast mechanisms are discussed in relation to the dopant regions themselves as well as the AlGaAs window at the p-region. A novel method of in situ observation of the SE profile changes resulting from reverse biasing these structures shows that the built-in potential may be deduced. The obtained value of 0.7 eV is lower than the conventional bulk value due to surface effects.",

keywords = "Conductance band, Dopant contrast, GaAs, High-resolution scanning electron microscopy, Quantum wells, Secondary electrons, Valence band",

author = "Enrique Grunbaum and Zahava Barkay and Yoram Shapira and Barnham, {Keith W.J.} and Bushnell, {David B.} and Ekins-Daukes, {Nicholas J.} and Massimo Mazzer and Peter Wilshaw",

year = "2009",

month = apr,

doi = "10.1017/S1431927609090205",

language = "אנגלית",

volume = "15",

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AU - Grunbaum, Enrique

AU - Barkay, Zahava

AU - Shapira, Yoram

AU - Barnham, Keith W.J.

AU - Bushnell, David B.

AU - Ekins-Daukes, Nicholas J.

AU - Mazzer, Massimo

AU - Wilshaw, Peter

PY - 2009/4

Y1 - 2009/4

N2 - The secondary electron (SE) signal over a cleaved surface of GaAs p-i-n solar cells containing stacks of quantum wells (QWs) is analyzed by high-resolution scanning electron microscopy. The InGaAs QWs appear darker than the GaAsP barriers, which is attributed to the differences in electron affinity. This method is shown to be a powerful tool for profiling the conduction band minimum across junctions and interfaces with nanometer resolution. The intrinsic region is shown to be pinned to the Fermi level. Additional SE contrast mechanisms are discussed in relation to the dopant regions themselves as well as the AlGaAs window at the p-region. A novel method of in situ observation of the SE profile changes resulting from reverse biasing these structures shows that the built-in potential may be deduced. The obtained value of 0.7 eV is lower than the conventional bulk value due to surface effects.

AB - The secondary electron (SE) signal over a cleaved surface of GaAs p-i-n solar cells containing stacks of quantum wells (QWs) is analyzed by high-resolution scanning electron microscopy. The InGaAs QWs appear darker than the GaAsP barriers, which is attributed to the differences in electron affinity. This method is shown to be a powerful tool for profiling the conduction band minimum across junctions and interfaces with nanometer resolution. The intrinsic region is shown to be pinned to the Fermi level. Additional SE contrast mechanisms are discussed in relation to the dopant regions themselves as well as the AlGaAs window at the p-region. A novel method of in situ observation of the SE profile changes resulting from reverse biasing these structures shows that the built-in potential may be deduced. The obtained value of 0.7 eV is lower than the conventional bulk value due to surface effects.

KW - Conductance band

KW - Dopant contrast

KW - GaAs

KW - High-resolution scanning electron microscopy

KW - Quantum wells

KW - Secondary electrons

KW - Valence band

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AN - SCOPUS:66349120571

SN - 1431-9276

VL - 15

SP - 125

EP - 129

JO - Microscopy and Microanalysis

JF - Microscopy and Microanalysis

IS - 2

ER -

Secondary electron emission contrast of quantum wells in GaAs p-i-n junctions

Abstract

Keywords

UN SDGs

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