Photoemission Study of the Physical Nature of the InP Near-Surface Defect States

1986 ◽  
Vol 77 ◽  
Author(s):  
K. K. Chin ◽  
R. Cao ◽  
T. Kendelewicz ◽  
K. Miyano ◽  
J. J. Yeh ◽  
...  
Keyword(s):  
Surface Defect ◽  
Physical Nature ◽  
Defect States ◽  
Band Bending ◽  
Near Surface ◽  
Fermi Level Pinning ◽  
Low Temperature Annealing ◽  
Donor States ◽  
Photoemission Study ◽  
P Type

ABSTRACTThe physical nature of the InP near-surface defect acceptor and donor states are studied by using photoemission spectroscopy. It is found that the In/n-InP(110) interface band bending does not start until the In coverage reaches about 0.3 monolayer (ML), while the In/p-InP(110) band bending is almost saturated at 0.3 ML. The annealing effect on the band bending of clean cleaved n-and p-type InP(llO) surfaces is also studied. It is found that annealing of the clean surface creates an irreversible band bending effect on the p-InP(110), but the n-InP(110) almost does not show any band bending after low temperature annealing. Based on these two striking differences in the band bending behavior of n- and p-type InP, it is proposed that the physical nature of InP near-surface defect acceptor and donor levels may be different and that phosphorus vacancies are the cause of p-InP surface Fermi level pinning.

Physical nature of the InP near-surface defect acceptor and donor states

1987 ◽  
Vol 36 (11) ◽  
pp. 5914-5919 ◽  
Author(s):  
K. Ken Chin ◽  
R. Cao ◽  
T. Kendelewicz ◽  
K. Miyano ◽  
J. -J. Yeh ◽  
...  
Keyword(s):  
Surface Defect ◽  
Physical Nature ◽  
Near Surface ◽  
Donor States

STM studies of Fermi-level pinning on the GaAs(001) surface

1993 ◽  
Vol 344 (1673) ◽  
pp. 533-543 ◽  
Keyword(s):  
Fermi Level ◽  
Valence Band ◽  
Surface Defects ◽  
Defect Density ◽  
Valence Band Maximum ◽  
Intrinsic Defect ◽  
Fermi Level Pinning ◽  
Donor States ◽  
P Type ◽  
Surface Donor

This paper reviews recent scanning tunnelling microsopy (STM) studies of Fermi-level pinning on the surface of both n- and p-type GaAs(001). The samples are all grown by molecular beam epitaxy and have a (2 x 4)/c(2 x 8) surface reconstruction. The STM has shown that on the surface of highly doped n-type GaAs(001) there is a high density of kinks in the dimer-vacancy rows of the (2 x 4) reconstruction. These kinks are found to be surface acceptors with approximately one electron per kink. The kinks form in exactly the required number to pin the Fermi-level of n-type GaAs(001) at an acceptor level close to mid gap, irrespective of doping level. The Fermi-level position is confirmed with tunnelling spectroscopy. No similar surface donor states are found on p-type GaAs(001). In this case Fermi-level pinning results from ‘intrinsic’ surface defects such as step edges. Since this intrinsic defect density is independent of doping, at high doping levels the Fermi-level on p-type GaAs(001) moves down in the band gap towards the valence band. Tunnelling spectroscopy on p-type GaAs(001) doped 10 19 cm -3 with Be shows the Fermi-level to be 150 mV above the valence band maximum

Electronic near-surface defect states of bare and metal covered n-GaN films observed by cathodoluminescence spectroscopy

1999 ◽  
Vol 28 (3) ◽  
pp. 308-313 ◽  
Author(s):  
A. P. Young ◽  
J. Schäfer ◽  
L. J. Brillson ◽  
Y. Yang ◽  
S. H. Xu ◽  
...  
Keyword(s):  
Surface Defect ◽  
Defect States ◽  
Near Surface ◽  
Cathodoluminescence Spectroscopy

Investigating the Relationship Between Atomic Structure and Carrier Depletion at [001] tilt Grain Boundaries in Ybco

1999 ◽  
Vol 574 ◽  
Author(s):  
N. D. Browning ◽  
J. P. Buban
Keyword(s):  
Grain Boundaries ◽  
Structural Unit ◽  
Boundary Plane ◽  
Charge Carriers ◽  
Mobile Charge ◽  
Band Bending ◽  
Donor States ◽  
P Type ◽  
The Relationship ◽  
Theoretical Analyses

AbstractRecent theoretical analyses [1] have suggested that the origin of the reduced Jc at grain boundaries in high-Tc superconductors may be band bending, which results in the depletion of mobile charge carriers at the boundaries. For this to occur in these p-type superconductors there must, by definition, be a high density of localized donor states in the boundary plane. Here we report a “structural unit” analysis of [0011 tilt grain boundaries in YBa2Cu 3O7-δ (YBCO) that indicates there may be a simple structural origin for such localized donor states.

scholarly journals Effects of graphene/BN encapsulation, surface functionalization and molecular adsorption on the electronic properties of layered InSe: a first-principles study

2018 ◽  
Vol 20 (18) ◽  
pp. 12939-12947 ◽  
Author(s):  
Andrey A. Kistanov ◽  
Yongqing Cai ◽  
Kun Zhou ◽  
Sergey V. Dmitriev ◽  
Yong-Wei Zhang
Keyword(s):  
Fermi Level ◽  
Work Function ◽  
Electronic Properties ◽  
Surface Functionalization ◽  
First Principles ◽  
Molecular Adsorption ◽  
Band Bending ◽  
Fermi Level Pinning ◽  
First Principles Study ◽  
P Type

A proper adoption of the n- or p-type dopants allows for the modulation of the work function, the Fermi level pinning, the band bending, and the photo-adsorbing efficiency near the InSe surface/interface.

The Intrinsic Formation Of Localized Electronic States At [001] Tilt Grain Boundaries In YBa2Cu3O7 And Their Effect On Jc

1999 ◽  
Vol 5 (S2) ◽  
pp. 156-157
Author(s):  
J. P. Buban ◽  
N. D. Browning
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Plane ◽  
Localized States ◽  
Contrast Imaging ◽  
Structural Units ◽  
Band Bending ◽  
Tilt Boundaries ◽  
Donor States ◽  
P Type

Grain boundaries have long been known to have a deleterious effect on the superconducting critical current that can be carried by YBa2Cu3O7-δ. Recent theoretical analyses have proposed that the origin of this behavior may be band bending, which results in the depletion of charge carriers at the grain boundaries. For this to occur in these p-type superconductors there must, by definition, be a high density of localized donor states in the boundary plane. Here we describe a structural feature intrinsic to all [001] tilt boundaries that may be the origin of these localized states.Direct atomic-resolution images of asymmetric [001] tilt grain boundary structures have been obtained using the Z-contrast imaging technique. The grain boundaries are observed to be composed of distinct structural units, as shown in figure 1. Within these structural units, a 2×1 reconstruction of the CuO columns is seen to occur. This reconstruction, which is caused by the constraint imposed on the structure by the sizes of the component atoms, leads to effective oxygen vacancies in the grain boundary plane (figure 2). Further oxygen annealing of the boundary cannot fill these vacancies as there is no space in the structure for more oxygen atoms.

Study of Temperature and Light Bias Effects on the Occupied Near Surface Defect Density in Hydrogenated Amorphous Silicon

1990 ◽  
Vol 192 ◽  
Author(s):  
Samer Aljishi ◽  
J. David Cohen ◽  
Lothar Ley
Keyword(s):  
Surface Defect ◽  
Defect Density ◽  
Hydrogenated Amorphous Silicon ◽  
Valence Band Edge ◽  
Equilibrium Conditions ◽  
Near Surface ◽  
Effects Of Temperature ◽  
P Type ◽  
Hydrogenated Amorphous ◽  
Surface Defect Density

ABSTRACTThe occupied density of states distributions in doped and undoped a-Si:H are investigated. Results reveal the presence of a distinct defect sub-band at 0.6 eV above the valence band edge Ey in n-type and in undoped films. In p-type films, this band is absent. Instead, a new band centered at 0.8 eV above Ev develops. This band is normally unoccupied and is therefore only seen under non-equilibrium conditions. A sub-band at this energy is also discovered in undoped a-Si:H films. The effects of temperature and light bias on these defect sub-bands are discussed.

An Investigation Of The Cause Of Initial Band Bending Of A Cleaved Clean n-GaAs(llO) Surface

1985 ◽  
Vol 54 ◽  
Author(s):  
K. K. Chin ◽  
R. Cao ◽  
K. Miyano ◽  
C. E. McCants ◽  
I. Lindau ◽  
...  
Keyword(s):  
Noble Metal ◽  
Noble Metals ◽  
Surface Defect ◽  
Poor Quality ◽  
Defect States ◽  
Band Bending ◽  
Metal Atoms ◽  
Barrier Formation ◽  
New Type ◽  
Induced Defects

ABSTRACTThe cause of the initial band bending on a clean n-GaAs(llO) surface of so-called “poor quality cleavage” has been controversial. To study this problem, a new type of geometric factor multi-metal evaporator has been designed, which enables us to obtain reproducible metal coverages as low as 10−4 monolayers. By following the early stages of band bending induced by the deposition of noble metals Cu, Ag and Au on n-GaAs (110) surfaces of different cleavage quality, it is found that a certain amount of initial band bending of a clean GaAs(llO) surface of poor quality cleavage corresponds to a certain amount of noble metal coverage (usually lower than 0.01 ML). This phenomenon can be explained in the following way. Any initial band bending on a clean n-GaAs(HO) surface is due to surface defect states created by the cleaving. These cleavage induced defects may be of the same nature as the interface states created by deposited noble metal atoms. Our experimental results will be discussed in the framework of the unified defect model of the Schottky barrier formation on III-V semiconductors.

Spectrum of Defect States in Porous Organic Low-k Dielectric Films, Annealed in Argon and Nitrogen

2003 ◽  
Vol 766 ◽  
Author(s):  
V. Ligatchev ◽  
T.K.S. Wong ◽  
T.K. Goh ◽  
Rusli Suzhu Yu
Keyword(s):  
Deep Level ◽  
Dielectric Films ◽  
Silicon Substrates ◽  
Reverse Bias Voltage ◽  
Defect States ◽  
Single Side ◽  
Sandwich Type ◽  
Transient Spectroscopy ◽  
P Type ◽  
Spectrum Deconvolution

AbstractDefect spectrum N(E) of porous organic dielectric (POD) films is studied with capacitance deep-level-transient-spectroscopy (C-DLTS) in the energy range up to 0.7 eV below conduction band bottom Ec. The POD films were prepared by spin coating onto 200mm p-type (1 – 10 Δcm) single-side polished silicon substrates followed by baking at 325°C on a hot plate and curing at 425°C in furnace. The film thickness is in the 5000 – 6000 Å range. The ‘sandwich’ -type NiCr/POD/p-Si/NiCr test structures showed both rectifying DC current-voltage characteristics and linear 1/C2 vs. DC reverse bias voltage. These confirm the applicability of the C-DLTS technique for defect spectrum deconvolution and the n-type conductivity of the studied films. Isochronal annealing (30 min in argon or 60 min in nitrogen) has been performed over the temperature range 300°C - 650°C. The N(E) distribution is only slightly affected by annealing in argon. However, the distribution depends strongly on the annealing temperature in nitrogen ambient. A strong N(E) peak at Ec – E = 0.55 – 0.60 eV is detected in all samples annealed in argon but this peak is practically absent in samples annealed in nitrogen at Ta < 480°C. On the other hand, two new peaks at Ec – E = 0.12 and 0.20 eV appear in the N(E) spectrum of the samples annealed in nitrogen at Ta = 650°C. The different features of the defect spectrum are attributed to different interactions of argon and nitrogen with dangling carbon bonds on the intra-pore surfaces.

Fermi level pinning and band bending in δ-doped BaSnO3

2021 ◽  
Vol 118 (5) ◽  
pp. 052101
Author(s):  
Youjung Kim ◽  
Hyeongmin Cho ◽  
Kookrin Char
Keyword(s):  
Fermi Level ◽  
Band Bending ◽  
Fermi Level Pinning
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