Band alignment at amorphous/crystalline silicon hetero-interfaces

2011 ◽  
Vol 1321 ◽  
Author(s):  
L. Korte ◽  
T. F. Schulze ◽  
C. Leendertz ◽  
M. Schmidt ◽  
B. Rech
Keyword(s):  
Photoelectron Spectroscopy ◽  
Experimental Error ◽  
Crystalline Silicon ◽  
Band Alignment ◽  
Low Energy ◽  
Surface Photovoltage ◽  
Band Offset ◽  
Conduction Band Offset ◽  
Silicon Heterojunctions ◽  
Deposition Conditions

ABSTRACTWe present an investigation of the band offsets in amorphous/crystalline silicon heterojunctions (a-Si:H/c-Si) using low energy photoelectron spectroscopy, ellipsometry and surface photovoltage data. For a variation of deposition conditions that lead to changes in hydrogen content and the thereby the a-Si:H band gap by ∼180 meV, we find that mainly the conduction band offset ΔEV varies, while ΔEC stays constant within experimental error. This result can be understood in the framework of charge neutrality (CNL) band lineup theory.

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

2012 ◽  
Vol 717-720 ◽  
pp. 721-724 ◽  
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.

Electronic Properties of GaN (0001) – Dielectric Interfaces

2004 ◽  
Vol 14 (01) ◽  
pp. 107-125 ◽  
Author(s):  
T. E. Cook ◽  
C. C. Fulton ◽  
W. J. Mecouch ◽  
R. F. Davis ◽  
G. Lucovsky ◽  
...  
Keyword(s):  
Electron Affinity ◽  
Photoelectron Spectroscopy ◽  
Band Alignment ◽  
Band Offset ◽  
Energy Bands ◽  
Interface Dipole ◽  
Conduction Band Offset ◽  
Dielectric Interfaces ◽  
P Type ◽  
Interface Type

The characteristics of clean n- and p-type GaN (0001) surfaces and the interface between this surface and SiO 2, Si 3 N 4, and HfO 2 have been investigated. Layers of SiO 2, Si3 N 4, or HfO 2 were carefully deposited to limit the reaction between the film and clean GaN surfaces. After stepwise deposition, the electronic states were measured with x-ray photoelectron spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS). A valence band offset (VBO) of 2.0±0.2 eV with a conduction band offset (CBO) of 3.6±0.2 eV was determined for the GaN / SiO 2 interface. The large band offsets suggest SiO 2 is an excellent candidate for passivation of GaN . For the GaN / Si 3 N 4, interface, type II band alignment was observed with a VBO of -0.5±0.2 eV and a CBO of 2.4±0.2 eV . While Si3 N 4 should passivate n-type GaN surfaces, it may not be appropriate for p-type GaN surfaces. A VBO of 0.3±0.2 eV with a CBO of 2.1±0.2 eV was determined for the annealed GaN / HfO 2 interface. An instability was observed in the HfO 2 film, with energy bands shifting ~0.4 eV during a 650°C densification anneal. The electron affinity measurements via UPS were 3.0, 1.1, 1.8, and 2.9±0.1 eV for GaN , SiO 2, Si 3 N 4, and HfO 2 surfaces, respectively. The deduced band alignments were compared to the predictions of the electron affinity model and deviations were attributed to a change of the interface dipole. Interface dipoles contributed 1.6, 1.1 and 2.0±0.2 eV to the band alignment of the GaN / SiO 2, GaN / Si 3 N 4, and GaN / HfO 2 interfaces, respectively. It was noted that the existence of Ga-O bonding at the heterojunction could significantly affect the interface dipole, and consequently the band alignment in relation to the GaN .

Experimental and First-Principles Studies of the Band Alignment at the HfO2/4H-SiC (0001) Interface

2006 ◽  
Vol 527-529 ◽  
pp. 1071-1074 ◽  
Author(s):  
Carey M. Tanner ◽  
Jong Woo Choi ◽  
Jane P. Chang
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Atomic Layer ◽  
Band Alignment ◽  
Functional Theory ◽  
X Ray ◽  
Conduction Band Offset ◽  
Mos Devices ◽  
Layer Deposition

The electronic properties of HfO2 films on 4H-SiC were investigated to determine their suitability as high-κ dielectrics in SiC power MOS devices. The band alignment at the HfO2/4HSiC interface was determined by X-ray photoelectron spectroscopy (XPS) and supported by density functional theory (DFT) calculations. For the experimental study, HfO2 films were deposited on ntype 4H-SiC by atomic layer deposition (ALD). XPS analysis yielded valence and conduction band offsets of 1.69 eV and 0.75 eV, respectively. DFT predictions based on two monoclinic HfO2/4HSiC (0001) structures agree well with this result. The small conduction band offset suggests the potential need for further interface engineering and/or a buffer layer to minimize electron injection into the gate oxide.

Large conduction band offset at SiO2 /β-Ga2 O3 heterojunction determined by X-ray photoelectron spectroscopy

2016 ◽  
Vol 253 (4) ◽  
pp. 623-625 ◽  
Author(s):  
Keita Konishi ◽  
Takafumi Kamimura ◽  
Man Hoi Wong ◽  
Kohei Sasaki ◽  
Akito Kuramata ◽  
...  
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Band Offset ◽  
X Ray ◽  
Conduction Band Offset

scholarly journals Capacitance Analysis of the Structures with the a-Si:H(i)/c-Si(p) Heterojunction for Solar-Cell Applications

2014 ◽  
Vol 65 (4) ◽  
pp. 254-258 ◽  
Author(s):  
Miroslav Mikolášek ◽  
Ján Jakaboviš ◽  
Vlastimil Řeháček ◽  
Ladislav Harmatha ◽  
Robert Andok
Keyword(s):  
Solar Cell ◽  
Amorphous Silicon ◽  
Crystalline Silicon ◽  
Amorphous Layer ◽  
Band Offset ◽  
Defect States ◽  
Conduction Band Offset ◽  
Silicon Heterojunction Solar Cell ◽  
Density Of Defect States ◽  
Passivated Silicon

Abstract In this paper we present the capacitance study of the intrinsic amorphous silicon/crystalline silicon heterostructure with the aim to gain insight on the heterointerface properties of a passivated silicon heterojunction solar cell. It is shown that due to the high density of defect states in the amorphous layer the structure has to be analyzed as a heterojunction. Using the analysis, the following values have been determined: conduction-band offset of 0.13 eV, electron affinity of 3.92 eV, and density of defect states in the intrinsic amorphous silicon being that of 4.14 X 1021m—3.

Band Alignment of CdS/Cu2ZnSnSe4 Heterointerface and Solar Cell Performances

MRS Advances ◽  
2017 ◽  
Vol 2 (53) ◽  
pp. 3157-3162 ◽  
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.

Band offset at TiO2/MDMO PPV and TiO2/PEDOT PSS interfaces studied using photoelectron spectroscopy

RSC Advances ◽  
2015 ◽  
Vol 5 (118) ◽  
pp. 97891-97897 ◽  
Author(s):  
R. S. Ajimsha ◽  
M. P. Joshi ◽  
S. Raj Mohan ◽  
Amit. K. Das ◽  
P. Misra ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Band Alignment ◽  
Band Offset

We report band alignment and band offset studies across the interfaces of hetero-structures of TiO2 with MDMO PPV and PEDOT PSS using photoelectron spectroscopy.

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