Photoluminescence Intensity Enhancement of GaAs by Vapor-Deposited GaS: a Rational Approach to Surface Passivation

1992 ◽  
Vol 282 ◽  
Author(s):  
Phillip P. Jenkins ◽  
Aloysius F. Hepp ◽  
Michael B. Power ◽  
Andrew R. Macinnes ◽  
Andrew R. Barrontt
Keyword(s):  
Surface Passivation ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Surface Recombination Velocity ◽  
Rational Approach ◽  
Cubic Phase ◽  
Photoluminescence Intensity ◽  
Band Bending ◽  
X Ray ◽  
Order Of Magnitude

ABSTRACTA two order-of-magnitude enhancement of photoluminescence intensity relative to untreated GaAs has been observed for GaAs surfaces coated with chemical vapor-deposited GaS. The increase in photoluminescence intensity can be viewed as an effective reduction in surface recombination velocity and/or band bending. The gallium cluster [(t-Bu)GaS]4 was used as a single-source precursor for the deposition of GaS thin films. The cubane core of the structurally-characterized precursor is retained in the deposited film producing a cubic phase. Furthermore, a near-epitaxial growth is observed for the GaS passivating layer. Films were characterized by transmission electron microscopy, X-ray powder diffraction, and X-ray photoelectron and Rutherford backscattering spectroscopies.

scholarly journals Surface passivation and optical characterization of Al2O3/a-SiCx stacks on c-Si substrates

2013 ◽  
Vol 4 ◽  
pp. 726-731 ◽  
Author(s):  
Gema López ◽  
Pablo R Ortega ◽  
Cristóbal Voz ◽  
Isidro Martín ◽  
Mónica Colina ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Optical Characterization ◽  
Surface Recombination Velocity ◽  
Carrier Injection ◽  
Si Substrates

The aim of this work is to study the surface passivation of aluminum oxide/amorphous silicon carbide (Al2O3/a-SiCx) stacks on both p-type and n-type crystalline silicon (c-Si) substrates as well as the optical characterization of these stacks. Al2O3 films of different thicknesses were deposited by thermal atomic layer deposition (ALD) at 200 °C and were complemented with a layer of a-SiCx deposited by plasma-enhanced chemical vapor deposition (PECVD) to form anti-reflection coating (ARC) stacks with a total thickness of 75 nm. A comparative study has been carried out on polished and randomly textured wafers. We have experimentally determined the optimum thickness of the stack for photovoltaic applications by minimizing the reflection losses over a wide wavelength range (300–1200 nm) without compromising the outstanding passivation properties of the Al2O3 films. The upper limit of the surface recombination velocity (S eff,max) was evaluated at a carrier injection level corresponding to 1-sun illumination, which led to values below 10 cm/s. Reflectance values below 2% were measured on textured samples over the wavelength range of 450–1000 nm.

Orientation Dependence Of Surface Passivation For Semi-Insulating Gaas

1996 ◽  
Vol 421 ◽  
Author(s):  
I.P. Koutzarov ◽  
C.H. Edirisinghe ◽  
H.E. Ruda ◽  
L.Z. Jedral ◽  
Q. Liu ◽  
...  
Keyword(s):  
Band Gap ◽  
Surface Passivation ◽  
Dielectric Film ◽  
Surface Recombination ◽  
Orientation Dependence ◽  
Film Deposition ◽  
Surface Recombination Velocity ◽  
Strong Increase ◽  
X Ray ◽  
Recombination Velocity

AbstractWe report on the orientation dependence ((100), (110) and (111) ) of photoluminescence (PL), photoreflectance (PR) and Surface Photo-Voltage (SPV) for sulfur passivated bulk semiinsulating (SI) GaAs. Near band gap PL peak intensities (bound-exciton and acceptor-related) were enhanced following (NH4)2S or S2Cl2 treatment of GaAs for all orientations. The reduction of surface recombination velocity (from PL data) was orientation dependent and especially pronounced for the case of (111)A and (111)B orientations. The effect of thin dielectric layers deposited on S-treated surfaces was also investigated, particularly for (100) and (111)A orientations. SPV data shows a strong increase in the above band gap signal after both Streatment and dielectric film deposition, which was higher than that measured for only S-treated surfaces. PR data showed an increase in the interfacial electric field following deposition of dielectric film. The results of absolute S-surface coverage measurements using particle-induced X-ray emission measurements were correlated with the optical characteristics.

Investigation of Surface Passivation in InAs/GaSb Strained-Layer-Superlattices Using Picosecond Excitation Correlation Measurement and Variable-Area Diode Array Surface Recombination Velocity Measurement

2005 ◽  
Vol 891 ◽  
Author(s):  
Zhimei Zhu ◽  
Elena Plis ◽  
Abdenour Amtout ◽  
Pallab Bhattacharya ◽  
Sanjay Krishna
Keyword(s):  
Infrared Detectors ◽  
Surface Passivation ◽  
Surface Recombination ◽  
Surface States ◽  
Depletion Region ◽  
Surface Recombination Velocity ◽  
Diode Array ◽  
Ammonium Sulfide ◽  
Picosecond Excitation ◽  
Recombination Velocity

ABSTRACTThe effect of ammonium sulfide passivation on InAs/GaSb superlattice infrared detectors was investigated using two complementary techniques, namely, picosecond excitation correlation (PEC) measurement and variable-area diode array (VADA) surface recombination velocity (SRV) measurement. PEC measurements were conducted on etched InAs/GaSb superlattice mesas, which were passivated in aqueous ammonium sulfide solutions of various strengths for several durations. The PEC signal's decay time constant (DTC) is proportional to carrier lifetimes. At 77 K the PEC signal's DTC of the as-grown InAs/GaSb superlattice sample was 2.0 ns, while that of the unpassivated etched sample was reduced to 1.2 ns by the surface states at the mesa sidewalls. The most effective ammonium sulfide passivation process increased the PEC signal's DTC to 10.4 ns. However it is difficult to isolate surface recombination from other processes that contribute to the lifetime using the PEC data, therefore a VADA SRV measurement was undertaken to determine the effect of passivation on surface recombination. The obtained SRV in the depletion region of the InAs/GaSb superlattice and GaSb junction was 1.1×106 cm/s for the unpassivated sample and 4.6×105 cm/s for the passivated sample. At 77 K the highest R0A value measured in our passivated devices was 2540 W cm2 versus 0.22 W cm2 for the unpassivated diodes. The results of the lifetime, the SRV and the R0A measurements indicate that ammonium sulfide passivation will improve the performance of InAs/GaSb superlattice infrared detectors.

scholarly journals Study on Annealing Process of Aluminum Oxide Passivation Layer for PERC Solar Cells

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1052
Author(s):  
Yu-Chun Huang ◽  
Ricky Wenkuei Chuang
Keyword(s):  
Carrier Lifetime ◽  
Defect Density ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Minority Carrier Lifetime ◽  
Atomic Layer ◽  
Film Structure ◽  
Open Circuit ◽  
Annealing Process ◽  
Surface Recombination Velocity

In this study, Atomic Layer Deposition (ALD) equipment was used to deposit Al2O3 film on a p-type silicon wafer, trimethylaluminum (TMA) and H2O were used as precursor materials, and then the post-annealing process was conducted under atmospheric pressure. The Al2O3 films annealed at different temperatures between 200–500 °C were compared to ascertain the effect of passivation films and to confirm the changes in film structure and thickness before and after annealing through TEM images. Furthermore, the negative fixed charge and interface defect density were analyzed using the C-V measurement method. Photo-induced carrier generation was used to measure the effective minority carrier lifetime, the implied open-circuit voltage, and the effective surface recombination velocity of the film. The carrier lifetime was found to be the longest (2181.7 μs) for Al2O3/Si post-annealed at 400 °C. Finally, with the use of VHF (40.68 MHz) plasma-enhanced chemical vapor deposition (PECVD) equipment, a silicon nitride (SiNx) film was plated as an anti-reflection layer over the front side of the wafer and as a capping layer on the back to realize a passivated emitter and rear contact (PERC) solar cell with optimal efficiency up to 21.54%.

scholarly journals Модификация электронных свойств поверхности n-InP(100) сульфидными растворами

2021 ◽  
Vol 55 (10) ◽  
pp. 895
Author(s):  
М.В. Лебедев ◽  
Т.В. Львова ◽  
А.Н. Смирнов ◽  
В.Ю. Давыдов
Keyword(s):  
Raman Spectroscopy ◽  
Electronic Properties ◽  
Electron Density ◽  
Surface Recombination ◽  
Depletion Layer ◽  
Surface Recombination Velocity ◽  
Photoluminescence Intensity ◽  
Surface Depletion ◽  
Recombination Velocity ◽  
Sulfide Solution

Photoluminescence and Raman spectroscopy are used to study the electronic properties of n-InP(100) surfaces passivated with different sulfide solutions. Such a passivation results in the increase in photoluminescence intensity of the semiconductor evidencing for the reduction in the surface recombination velocity. The increase in the photoluminescence intensity is accompanied by the narrowing of the surface depletion layer, as well as by the increase of the electron density in the probed volume of InP. The efficiency of electronic passivation of the n-InP(100) surface depends on the composition of the sulfide solution.

Surface Recombination Investigation in Thin 4H-SiC Layers

1970 ◽  
Vol 17 (2) ◽  
pp. 119-124 ◽  
Author(s):  
Karolis GULBINAS ◽  
Vytautas GRIVICKAS ◽  
Haniyeh P. MAHABADI ◽  
Muhammad USMAN ◽  
Anders HALLÉN
Keyword(s):  
Surface Passivation ◽  
Surface Recombination ◽  
Atomic Layer ◽  
Surface Recombination Velocity ◽  
Lifetime Distributions ◽  
Carrier Lifetimes ◽  
Layer Deposition ◽  
Type Layer ◽  
Recombination Velocity ◽  
P Type

n- and p-type 4H-SiC epilayers were grown on heavily doped SiC substrates. The thickness of the p-type layer was 7 µm and the doping level around 1017 cm 3, while the n-type epilayers were 15 µm thick and had a doping concentration of 3 - 5*1015 cm 3. Several different surface treatments were then applied on the epilayers for surface passivation: SiO2 growth, Al2O3 deposited by atomic layer deposition, and Ar-ion implantation. Using collinear pump - probe technique the effective carrier lifetimes were measured from various places and statistical lifetime distributions were obtained. For surface recombination evaluation, two models are presented. One states that surface recombination velocity (SRV) is equal on both the passivation/epi layer interface (S2) and the deeper interface between the epilayer and the SiC substrate i. e. (S1 = S2). The other model is simulated assuming that SRV in the epilayer/substrate (S1) interface is constant while in the passivation layer/epilayer (S2) interface SRV can be varied S2 < S1. Empirical nomograms are presented with various parameters sets to evaluate S2 values. We found that on the investigated 4H-SiC surfaces S2 ranges from 3x104 to 5x104 assuming that the bulk lifetime is 4 (µs. In Ar+ implanted surfaces S2 is between (105 - 106) cm/s.http://dx.doi.org/10.5755/j01.ms.17.2.479

Nitridation by NO Or N2O of Si-SiO2 Interfaces

1999 ◽  
Vol 567 ◽  
Author(s):  
A. P. Caricato ◽  
F. Cazzaniga ◽  
G. F. Cerofolini ◽  
B. Crivelli ◽  
M. L. Polignano ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Nature ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Oxide Surface ◽  
Complementary Information ◽  
X Ray ◽  
Recombination Velocity ◽  
Foreign Species

ABSTRACTX-ray photoelectron spectroscopy (XPS) and photocurrent measurements for the determination of surface recombination velocity provide complementary information on the structure of the Si-SiO2 interface, being sensitive to the chemical nature of foreign species at the interface the former, and to intrinsic defects the latter. The comparison of the XPS N(1s) peaks determined for the Si-Si0 2 interfaces nitrided in NO or N2O ambients is useful to identify the species responsible for the broadening of the peak. In fact, nitridation by NO is mainly responsible for the formation of Si3N moieties at the silicon surface in which silicon atoms are partially oxidized; while nitridation by N2O proceeds with the oxidation of Si – Si backbonds to Si – N bonds, thus resulting in the formation of N(Si(O-)3)3 groups embedded in the oxide. Surface recombination velocity by photocurrent measurements gives evidence that nitridation in N2O is associated with an appreciable co-oxidation, while nitridation in NO is mainly associated with the passivation of interface states. Furthermore N2O and NO nitridation are responsible for different morphologies of the nitrided layers.

HYDROGEN IN CRYSTALLINE SEMICONDUCTORS: PART II–III–V COMPOUNDS

1994 ◽  
Vol 08 (10) ◽  
pp. 1247-1342 ◽  
Author(s):  
S.J. PEARTON
Keyword(s):  
Surface Passivation ◽  
Surface Recombination ◽  
Neutral Hydrogen ◽  
Chemical Vapor ◽  
Shallow Donor ◽  
Donor And Acceptor ◽  
Vibrational Bands ◽  
Deposition Processes ◽  
P Type ◽  
Metallic Impurities

The properties of hydrogen in III–V semiconductors are reviewed. Atomic hydrogen is found to passivate the electrical activity of shallow donor and acceptor dopants in virtually all III–V materials, including GaAs, Alx Ga1−x As, InP, InGaAs, GaP, InAs, GaSb, InGaP, AlInAs and AlGaAsSb. The passivation is due to the formation of neutral dopant-hydrogen complexes, with hydrogen occupying a bond-centered position in p-type semiconductors and an anti-bonding site in n-type materials. The dopants are reactivated by annealing at ≤400° C. The neutral hydrogen-dopant complexes have characteristic vibrational bands, around 2000cm−1 for stretching modes and 800cm−1 for wagging modes. Deep levels such as EL2, DX and metallic impurities are also passivated by hydrogen. The diffusivity of hydrogen is high in III–V semiconductors and unintentional incorporation can occur during epitaxial growth, annealing in H2, dry etching, water boiling, wet etching or chemical vapor deposition processes, Surface passivation by (NH4)xS or NH3 plasma treatment is also effective in lowering surface recombination velocities in many III-V semiconductors.

Interface Study Of Nanocrystalline Silicon and Crystalline Silicon Using Microwave Photoconductivity Decay

2006 ◽  
Vol 910 ◽  
Author(s):  
Mahdi Farrokh Baroughi ◽  
Siva Sivoththaman
Keyword(s):  
Crystalline Silicon ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Interface Region ◽  
Surface Recombination Velocity ◽  
Si Substrate ◽  
Photoconductivity Decay ◽  
Recombination Velocity ◽  
Si Films

AbstractThis paper presents a measurement technique for studying of the interface between a nanocrystalline silicon (nc-Si) film and a crystalline silicon (c-Si) substrate using microwave photoconductivity decay (MWPCD). The nc-Si films were deposited using plasma enhanced chemical vapor deposition of highly hydrogen-diluted silane. The films were deposited on both sides of the high purity float-zone (FZ) Si wafers. The high resolution transmission electron microscope (HRTEM) analysis of the interface and the characterization of the effective excess carrier lifetime of the samples using MWPCD revealed the following results: (i) The crystallinity of the deposited nc-Si films is very high. The nc-Si film follows the crystal orientation of the substrate such that not a well-defined boundary between nc-Si film and the c-Si substrate is observed. (ii) A surface recombination velocity of less than 10 cm/s was measured for the interface region of the nc-Si/c-Si junctions. (iii) A small discontinuity in the band-energy diagram of the interface region was observed.

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