Measurements of the Band Offset of SiO2 on Clean GaN

AbstractThe band alignment of SiO2 and GaN is important for passivation of high voltage devices and for gate insulator applications. In this study XPS and UPS techniques are employed to determine the electronic states as SiO2 is deposited onto a clean GaN surface. The substrate was epitaxially grown n-type GaN on 6H-SiC (0001) substrates with an AlN (0001) buffer layer. The GaN surface was atomically cleaned via a 860°C anneal in an NH3 atmosphere. For the clean GaN surface, upward band bending of ~0.3 ±0.1 eV was measured, and the electron affinity was measured to be ~2.9 eV. Layers of Si were deposited on the GaN surface via Molecular Beam Epitaxy (MBE), and the Si was oxidized by a remote O2 plasma. The oxidation of the Si occurred without oxidizing the GaN. Densification of the created SiO2 film was achieved by annealing the substrate at 650°C. Surface analysis techniques were performed after each process, and yielded a valence band offset of ~2.0 eV, and a conduction band offset of ~3.6 eV for the GaN-SiO2 interface.

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Band Alignment of CdS/Cu2ZnSnSe4 Heterointerface and Solar Cell Performances

MRS Advances ◽

10.1557/adv.2017.315 ◽

2017 ◽

Vol 2 (53) ◽

pp. 3157-3162 ◽

Cited By ~ 1

Author(s):

Takehiko Nagai ◽

Shinho Kim ◽

Hitoshi Tampo ◽

Kang Min Kim ◽

Hajime Shibata ◽

...

Keyword(s):

Conduction Band ◽

Band Alignment ◽

Photoemission Spectroscopy ◽

Band Offset ◽

Valence Band Offset ◽

X Ray ◽

Heterojunction Solar Cells ◽

Conduction Band Offset ◽

Ultraviolet Photoemission Spectroscopy ◽

Large Spike

ABSTRACTWe determined that the conduction band offset (CBO) and the valence band offset (VBO) at the CdS/ Cu2ZnSnSe4 (CZTSe) heterointerface are +0.56 and +0.89eV, respectively, by using X-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS) and inversed photoemission spectroscopy (IPES). A positive CBO value, so-called “spike” structure, means that the position of conduction band becomes higher than that of absorber layer. The evaluated CBO of +0.56 eV suggests that the conduction band alignment at CdS/CZTSe interface is enough to become an electron barrier. Despite such a large spike structure in the conduction band at the interface, a conversion efficiency of 8.7 % could be obtained for the CdS/CZTSe heterojunction solar cells.

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CONSTRUCTION OF SnO2/SiO2/Si HETEROJUNCTION AND ITS LINEUP USING I–V AND C–V MEASUREMENTS

International Journal of Modern Physics B ◽

10.1142/s0217979211102022 ◽

2011 ◽

Vol 25 (29) ◽

pp. 3863-3869 ◽

Cited By ~ 25

Author(s):

EVAN T. SALEM ◽

IBRAHIM R. AGOOL ◽

MARWA A. HASSAN

Keyword(s):

Experimental Data ◽

Thermal Evaporation ◽

Energy Band Diagram ◽

Metal Films ◽

Band Offset ◽

Band Diagram ◽

Thermal Evaporation Technique ◽

Valence Band Offset ◽

Conduction Band Offset ◽

Evaporation Technique

Near-ideal n- SnO 2/n- Si heterojunction band edge lineup has been investigated with aid of I–V and C–V measurements. The heterojunction was manufactured by rapid thermal oxidation of Sn metal films prepared by thermal evaporation technique on monocrystalline n-type silicon. The experimental data of the conduction band offset ΔEc and valence band offset ΔEc were compared with theoretical values. The band offset ΔEc = 0.55 eV and ΔEv = 1.8 eV obtained at 300 K. The energy band diagram of n- SnO 2/n- Si HJ was constructed. C–V measurements depict that the junction was an abrupt type and the built-in voltage was determined from 1/C2–V plot.

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Valence band offset at GaN/β-Si3N4 and β-Si3N4/Si(111) heterojunctions formed by plasma-assisted molecular beam epitaxy

Thin Solid Films ◽

10.1016/j.tsf.2011.10.051 ◽

2012 ◽

Vol 520 (15) ◽

pp. 4911-4915 ◽

Cited By ~ 10

Author(s):

Mahesh Kumar ◽

Basanta Roul ◽

Thirumaleshwara N. Bhat ◽

Mohana K. Rajpalke ◽

A.T. Kalghatgi ◽

...

Keyword(s):

Molecular Beam Epitaxy ◽

Valence Band ◽

Molecular Beam ◽

Band Offset ◽

Valence Band Offset

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High valence‐band offset of GaSbAs‐InAlAs quantum wells grown by molecular beam epitaxy

Applied Physics Letters ◽

10.1063/1.108229 ◽

1992 ◽

Vol 61 (19) ◽

pp. 2317-2319 ◽

Cited By ~ 18

Author(s):

P. W. Yu ◽

D. C. Reynolds ◽

B. Jogai ◽

J. Loehr ◽

C. E. Stutz

Keyword(s):

Molecular Beam Epitaxy ◽

Quantum Wells ◽

Valence Band ◽

Molecular Beam ◽

Band Offset ◽

Valence Band Offset ◽

High Valence Band

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Impact of Interface Defect Passivation on Conduction Band Offset at SiO2/4H-SiC Interface

Materials Science Forum ◽

10.4028/www.scientific.net/msf.717-720.721 ◽

2012 ◽

Vol 717-720 ◽

pp. 721-724 ◽

Cited By ~ 5

Author(s):

Takuji Hosoi ◽

Takashi Kirino ◽

Atthawut Chanthaphan ◽

Yusuke Uenishi ◽

Daisuke Ikeguchi ◽

...

Keyword(s):

Conduction Band ◽

Photoelectron Spectroscopy ◽

Hydrogen Gas ◽

Band Alignment ◽

Band Offset ◽

Partial Recovery ◽

Conduction Band Offset ◽

Interface Defect ◽

Defect Passivation ◽

Thermally Grown

The change in energy band alignment of thermally grown SiO2/4H-SiC(0001) structures due to an interface defect passivation treatment was investigated by means of synchrotron radiation photoelectron spectroscopy (SR-PES) and electrical characterization. Although both negative fixed charge and interface state density in SiO2/SiC structures were effectively reduced by high-temparature hydrogen gas annealing (FGA), the conduction band offset (ΔEc) at the SiO2/SiC interface was found to be decreased by about 0.1 eV after FGA. In addition, a subsequent vacuum annealing to induce hydrogen desorption from the interface resulted in not only a slight degradation in interface property but also a partial recovery of ΔEc value. These results indicate that the hydrogen passivation of negatively charged defects near the thermally grown SiO2/SiC interface causes the reduction in conduction band offset. Therefore, the tradeoff between interface quality and conduction band offset for thermally grown SiO2/SiC MOS structure needs to be considered for developing SiC MOS devices.

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Gaas Etching by C12 and HCI: Ga- vs. As- Limited Etching

MRS Proceedings ◽

10.1557/proc-334-413 ◽

1993 ◽

Vol 334 ◽

Author(s):

Chaochin Su ◽

Zi-Guo Dai ◽

Hui-Qi Hou ◽

Ming Xi ◽

Matthew F. Vernon ◽

...

Keyword(s):

Surface Analysis ◽

Room Temperature ◽

Molecular Beam ◽

Molecular Beam Scattering ◽

Analysis Techniques ◽

Surface Analysis Techniques ◽

Beam Scattering ◽

Two Systems ◽

Measurable Rate ◽

Kinetics Of

AbstractResults in the literature indicate that C12 etches GaAs at room temperature but HCl etches GaAs at a measurable rate only at temperatures above ∼670 K. In this work, molecular beam scattering and surface analysis techniques have been applied to address the fundamental kinetic differences between these two systems. The results indicate that the onset of GaAs etching by C12 is determined by the kinetics of Ga-removal as GaC13 while etching by HCl is limited by As evaporation as As2. The results also suggest that HCl selectively etches gallium from GaAs at temperatures between 600 and 650 K.

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CONSTRUCTION OF ANISOTYPE CdS/Si HETEROJUNCTION AND LINEUP USING I–V AND C–V MEASUREMENTS

Modern Physics Letters B ◽

10.1142/s0217984906012158 ◽

2006 ◽

Vol 20 (28) ◽

pp. 1833-1838 ◽

Cited By ~ 1

Author(s):

RAID A. ISMAIL ◽

ABDUL-MAJEED E. AL-SAMARAI ◽

OMAR A. ABDULRAZAQ

Keyword(s):

Spray Pyrolysis Technique ◽

Energy Band Diagram ◽

Chemical Spray Pyrolysis ◽

Band Offset ◽

Band Diagram ◽

Valence Band Offset ◽

Conduction Band Offset ◽

Chemical Spray Pyrolysis Technique ◽

Chemical Spray ◽

First Time

Near-ideal p-CdS/n-Si heterojunction (HJ) band edge lineup has been investigated for the first time with the aid of I–V and C–V measurements. The heterojunction was obtained by the deposition of CdS films prepared by chemical spray pyrolysis technique (CSP), on the monocrystalline n-type silicon. The experimental data of the conduction band offset, ΔEc and the valence band offset, ΔEc were compared with theoretical values. The band offsets ΔEc=530 meV and ΔEv=770 meV were obtained at 300 K. The energy band diagram of p-CdS/n-Si HJ was constructed. The C–V measurements depicted that the junction was an abrupt type and the built-in voltage was determined from the C-2–V plot.

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Optical Investigation of the Band Offset of CdxZn1−xTe /ZnTe and ZnSexTe1−x/ZnTe Superlattices

MRS Proceedings ◽

10.1557/proc-198-427 ◽

1990 ◽

Vol 198 ◽

Author(s):

Y. Rajakarunanayake ◽

M. C. Phillips ◽

J. O. Mccaldin ◽

D. H. Chow ◽

D. A. Collins ◽

...

Keyword(s):

Valence Band ◽

Band Alignment ◽

Band Offset ◽

Type I ◽

Optical Investigation ◽

Type Ii ◽

Carrier Injection ◽

Valence Band Offset ◽

Small Component ◽

Strained Layer Superlattices

ABSTRACTWe have analyzed photoluminescence spectra from CdxZnl−xTe /ZnTe and ZnSexTel−x/ZnTe strained layer superlattices grown by MBE, and obtained the band offsets by fitting to theory. We find that the valence band offset of the CdTe/ZnTe system is quite small (-50± 160 meV). In CdxZnl−xTe /ZnTe superlattices, the electrons and heavy holes are confined in the CdxZn1−xTe layers (type I), while the light holes are confined in the ZnTe layers (type II). On the other hand, the photoluminescence data from the ZnSexTe1−x /ZnTe superlattices suggest that the band alignment is type II, with a large valence band offset (−907 ± 120 meV). We also investigated the band bowing in the ZnSexTel−x alloys by optical spectroscopy, and found that there is only a small component of bowing in the valence band, while most of the bowing occurs in the conduction band. Based on our results for band alignments, we evaluate the prospects for minority carrier injection in wide bandgap heterostructures based on ZnSe, ZnTe, and CdTe.

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Sb2S3/TiO2 Heterojunction Photocathodes: Band Alignment and Water Splitting Properties

10.26434/chemrxiv.12110208 ◽

2020 ◽

Author(s):

Rajiv Ramanujam Prabhakar ◽

Thomas Moehl ◽

Sebastian Siol ◽

Jihye Suh ◽

David Tilley

Keyword(s):

Buffer Layer ◽

Water Splitting ◽

Elemental Sulfur ◽

Band Alignment ◽

Band Bending ◽

Co Catalyst ◽

Conduction Band Offset ◽

Photovoltaic Applications ◽

Earth Abundant ◽

Further Development

Antimony sulfide (Sb2S3) is a promising light absorbing semiconductor for photovoltaic applications, though it remains vastly unexplored for photoelectrochemical water splitting. Sb2S3 was synthesized by a simple sulfurization of electrodeposited antimony metal at relatively low temperatures (240-300°C) with elemental sulfur. Using a TiO2 buffer layer and a platinum co-catalyst, photocurrent densities up to ~ 9 mA cm-2 were achieved at -0.4 V vs. RHE in 1 M H2SO4 under one sun illumination. Using XPS band alignment studies and potential dependent IPCE measurements, a conduction band offset of 0.7 eV was obtained for the Sb2S3/TiO2 junction as well as an unfavorable band bending at the heterointerface, which explains the low photovoltage that was observed (~ 0.1 V). Upon inserting an In2S3 buffer layer, which offers a better band alignment, a 0.15 V increase in photovoltage was obtained. The excellent PEC performance and the identification of the origin of the low photovoltage of the Sb2S3 photocathodes in this work pave the way for the further development of this promising earth abundant light absorbing semiconductor for solar fuels generation.

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Theoretical Study of InAsSb/InTlSB Superlattice for the Far Infrared Detector

MRS Proceedings ◽

10.1557/proc-421-395 ◽

1996 ◽

Vol 421 ◽

Cited By ~ 3

Author(s):

S. Iyer ◽

S. Chowdhury-Nagle ◽

J. Li ◽

K.K. Bajaj

Keyword(s):

Heavy Hole ◽

Infrared Detector ◽

Far Infrared ◽

Structural Quality ◽

Accurate Information ◽

Band Offset ◽

Type I ◽

Valence Band Offset ◽

Conduction Band Offset ◽

Lattice Matched

AbstractWe propose a novel superlattice (SL) InAsySb1−y)/InxTl1−xSb lattice matched to InSb for a potential application as an infrared detector material in the 8–12 μm wavelength range. We report on the results of energy band calculations for this SL using the modified Kronig-Penney model. Our preliminary calculations indicate that InAs0.07Sb0.93/In0.93Tl0.07Sb would exhibit a type-I SL with conduction band offset of 34 meV and valence band offset of 53 meV at 0K. Due to the lack of accurate information on material parameters, namely, energy offsets and effective masses of InTlSb, these were estimated by comparison with the behavior of HgCdTe system. The theory predicts three heavy hole subbands and one partially confined electron in the 30Å InAs0.07Sb0.93/100Å In0.93Tl0.07Sb SL. The band gap of the SL was computed to be 0.127 eV (9.7 μm). It is expected that this SL will allow improvements in the InTlSb epilayers’ structural quality as it will be sandwiched between higher quality zincblende InAsSb layers.

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