Type II Band Alignment inSi1−xGex/Si(001)Quantum Wells: The Ubiquitous Type I Luminescence Results from Band Bending

AbstractGaAsSb (N) superattices (SLs) grown on InP substrates using metalorganic vapor phase epitaxy are investigated by high resolution X-ray diffraction (XRD), low temperature photoluminescence (PL), and high resolution transmission electron microscopy (TEM). XRD shows very sharp satellite peaks and pendellosung fringes, which indicates excellent crystalline quality and abrupt interfaces in the GaAsSb (N)/InP SL, with Sb varies with 0.2 to 0.7. Low temperature PL shows clearly different features between the 25% Sb and 44% Sb samples. A band alignment difference is proposed to explain these behaviors. Experimental data establishes that the transition from a type-I to a type-II heterostructure occurs for a Sb-content of approximately 40%, which agrees well with the prediction by Model Solid Theory. While N incorporation degrades the PL intensity, it also provides the greater electron confinement needed to achieve mid-IR emission from GaAsSbN/GaAsSb type-II QWs

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OPTICAL STUDIES OF TYPE I AND TYPE II RECOMBINATION IN GaAs-AlAs QUANTUM WELLS

Le Journal de Physique Colloques ◽

10.1051/jphyscol:19875112 ◽

1987 ◽

Vol 48 (C5) ◽

pp. C5-525-C5-528 ◽

Cited By ~ 2

Author(s):

K. J. MOORE ◽

P. DAWSON ◽

C. T. FOXON

Keyword(s):

Quantum Wells ◽

Type I ◽

Type Ii ◽

Optical Studies

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Excitonic properties of type-I and type-II Si∕Si1−xGex quantum wells

Journal of Applied Physics ◽

10.1063/1.2723857 ◽

2007 ◽

Vol 101 (11) ◽

pp. 113703 ◽

Cited By ~ 4

Author(s):

Andrey Chaves ◽

J. Costa e Silva ◽

J. A. K. Freire ◽

G. A. Farias

Keyword(s):

Quantum Wells ◽

Type I ◽

Type Ii ◽

Excitonic Properties

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Type I–type II anticrossing and enhanced Stark effect in asymmetric coupled quantum wells

Applied Physics Letters ◽

10.1063/1.100209 ◽

1988 ◽

Vol 53 (26) ◽

pp. 2584-2586 ◽

Cited By ~ 47

Author(s):

J. E. Golub ◽

P. F. Liao ◽

D. J. Eilenberger ◽

J. P. Harbison ◽

L. T. Florez ◽

...

Keyword(s):

Quantum Wells ◽

Stark Effect ◽

Type I ◽

Type Ii ◽

Coupled Quantum Wells

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Efficient Photocatalytic Hydrogen Evolution via Band Alignment Tailoring: Controllable Transition from Type-I to Type-II

Small ◽

10.1002/smll.201702163 ◽

2017 ◽

Vol 13 (41) ◽

pp. 1702163 ◽

Cited By ~ 23

Author(s):

Zhongzhou Cheng ◽

Fengmei Wang ◽

Tofik Ahmed Shifa ◽

Chao Jiang ◽

Quanlin Liu ◽

...

Keyword(s):

Hydrogen Evolution ◽

Band Alignment ◽

Type I ◽

Type Ii ◽

Photocatalytic Hydrogen Evolution

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Ultrafast Charge Separation in Bilayer WS2/Graphene Heterostructure Revealed by Time- and Angle-Resolved Photoemission Spectroscopy

Frontiers in Physics ◽

10.3389/fphy.2021.668149 ◽

2021 ◽

Vol 9 ◽

Author(s):

Razvan Krause ◽

Mariana Chávez-Cervantes ◽

Sven Aeschlimann ◽

Stiven Forti ◽

Filippo Fabbri ◽

...

Keyword(s):

Charge Separation ◽

Graphene Layer ◽

Optoelectronic Devices ◽

Visible Spectral Range ◽

Band Alignment ◽

Photoemission Spectroscopy ◽

Type I ◽

Type Ii ◽

Angle Resolved Photoemission Spectroscopy ◽

Indirect Band Gap

Efficient light harvesting devices need to combine strong absorption in the visible spectral range with efficient ultrafast charge separation. These features commonly occur in novel ultimately thin van der Waals heterostructures with type II band alignment. Recently, ultrafast charge separation was also observed in monolayer WS2/graphene heterostructures with type I band alignment. Here we use time- and angle-resolved photoemission spectroscopy to show that ultrafast charge separation also occurs at the interface between bilayer WS2 and graphene indicating that the indirect band gap of bilayer WS2 does not affect the charge transfer to the graphene layer. The microscopic insights gained in the present study will turn out to be useful for the design of novel optoelectronic devices.

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Indirect transitions between barrier (X) electrons and two-dimensional hole gas in mixed type I - type II quantum wells

Springer Proceedings in Physics - Proceedings of the 25th International Conference on the Physics of Semiconductors Part I ◽

10.1007/978-3-642-59484-7_270 ◽

2001 ◽

pp. 571-572

Author(s):

R. Guliamov ◽

E. Lifshitz ◽

E. Cohen ◽

Arza Ron ◽

L. N. Pfeiffer

Keyword(s):

Quantum Wells ◽

Mixed Type ◽

Type I ◽

Type Ii ◽

Two Dimensional ◽

Type Ii Quantum Wells

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PN/PAs-WSe2 van der Waals heterostructures for solar cell and photodetector

Scientific Reports ◽

10.1038/s41598-020-73152-7 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Xinyi Zheng ◽

Yadong Wei ◽

Kaijuan Pang ◽

Ngeywo Kaner Tolbert ◽

Dalin Kong ◽

...

Keyword(s):

Refractive Index ◽

Solar Cells ◽

Negative Refractive Index ◽

Wide Spectrum ◽

Van Der Waals ◽

Band Alignment ◽

Ultraviolet Region ◽

Type I ◽

Type Ii ◽

Van Der Waals Heterostructures

Abstract By first-principles calculations, we investigate the geometric stability, electronic and optical properties of the type-II PN-WSe2 and type-I PAs-WSe2 van der Waals heterostructures(vdWH). They are p-type semiconductors with indirect band gaps of 1.09 eV and 1.08 eV based on PBE functional respectively. By applying the external gate field, the PAs-WSe2 heterostructure would transform to the type-II band alignment from the type-I. With the increasing of magnitude of the electric field, two heterostructures turn into the n-type semiconductors and eventually into metal. Especially, PN/PAs-WSe2 vdWH are both high refractive index materials at low frequencies and show negative refractive index at high frequencies. Because of the steady absorption in ultraviolet region, the PAs-WSe2 heterostructure is a highly sensitive UV detector material with wide spectrum. The type-II PN-WSe2 heterostructure possesses giant and broadband absorption in the near-infrared and visible regions, and its solar power conversion efficiency of 13.8% is higher than the reported GaTe–InSe (9.1%), MoS2/p-Si (5.23%) and organic solar cells (11.7%). It does project PN-WSe2 heterostructure a potential for application in excitons-based solar cells.

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TEMPERATURE DEPENDENCE OF PHOTOLUMINESCENCE OF FLAT AND UNDULATED SiGe/Si MULTIPLE QUANTUM WELLS

International Journal of Modern Physics B ◽

10.1142/s0217979202015108 ◽

2002 ◽

Vol 16 (28n29) ◽

pp. 4211-4214 ◽

Cited By ~ 3

Author(s):

B. W. CHENG ◽

J. G. ZHANG ◽

Y. H. ZUO ◽

R. W. MAO ◽

C. J. HUANG ◽

...

Keyword(s):

Elevated Temperature ◽

Quantum Wells ◽

Blue Shift ◽

Band Alignment ◽

Multiple Quantum Wells ◽

Luminescence Spectra ◽

Multiple Quantum ◽

Type Ii ◽

Thermally Activated ◽

Strained Sige

Photoluminescence (PL) of strained SiGe/Si multiple quantum wells (MQW) with flat and undulated SiGe well layers was studied at different temperature. With elevated temperature from 10K, the no-phonon (NP) peak of the SiGe layers in the flat samples has firstly a blue shift due to the dominant transition converting from bound excitons (BE) to free excitons (FE), and then has a red shift when the temperature is higher than 30K because of the narrowing of the band gap. In the undulated sample, however, monotonous blue shift was observed as the temperature was elevated from 10 K to 287 K. The thermally activated electrons, confined in Si due to type-II band alignment, leak into the SiGe crest regions, and the leakage is enhanced with the elevated temperature. It results in a blue shift of the SiGe luminescence spectra.

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