Photoluminescence measurement of sidewall damage in etched InGaAsP/lnP and GaAs/AIGaAs microstructures

1988 ◽  
Vol 144 ◽  
Author(s):  
P. Grabbe ◽  
A. Scherer ◽  
K. Kash ◽  
R. Bhat ◽  
J. Harbison ◽  
...  
Keyword(s):  
Recombination Rate ◽  
Surface Recombination ◽  
Dry Etching ◽  
Etching Time ◽  
Carrier Recombination ◽  
Damage Depth ◽  
Etching Parameters ◽  
Subsequent Chemical

ABSTRACTWe report the first investigation of the effect of dry etching parameters on the sidewall carrier recombination rate of GaAs/AIGaAs and lnPilnGaAsP microstructures. Surface recombination was measured as a function of ion voltage and etching time. The increase in recombination rate due to etching can be reversed by subsequent chemical removal of the immediate sidewall layer. By monitoring the recovery in recombination rate as a function of the amount of sidewall layer removed, the effective damage depth is inferred.

IR and MW Absorption Techniques for Bulk and Surface Recombination Control in High-Quaiity Silicon

1995 ◽  
Vol 386 ◽  
Author(s):  
A. Kaniava ◽  
U. Menczigar ◽  
J. Vanhellemont ◽  
J. Poortmans ◽  
A. L. P. Rotondaro ◽  
...  
Keyword(s):  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Silicon Substrates ◽  
Injection Level ◽  
Effective Lifetime ◽  
Carrier Recombination ◽  
High Injection Level ◽  
High Injection ◽  
Wide Range ◽  
Recombination Velocity

ABSTRACTThe carrier recombination rate in high-quality FZ and Cz silicon substrates is studied by contactless infrared and microwave absorption techniques. Different surface treatments covering a wide range of surface recombination velocity have been used for the separation of bulk and surface recombination components and evaluating of the efficiency of passivation. Limitations of effective lifetime approach are analyzed specific for low and high injection level. Sensitivity limits of the techniques for iron contamination are discussed

The Effect of Catalyst on Carbon Nanotubes (CNTs) Synthesized by Catalytic Chemical Vapor Deposition (CVD) Technique

2011 ◽  
Vol 364 ◽  
pp. 232-237 ◽  
Author(s):  
S.Y. Lim ◽  
M.M. Norani
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Dry Etching ◽  
Wet Etching ◽  
Etching Time ◽  
Catalytic Chemical Vapor Deposition ◽  
Catalyst Pretreatment ◽  
Diameter Range

Catalyst plays a crucial role in determining the characteristics of carbon nanotubes (CNTs) produced by using thermal catalytic chemical vapor deposition (CVD). It is essential to investigate how the catalyst preparation affects the characteristics of CNTs because certain application demands specific size for optimum performance. This study reports the effect of the types of catalyst and the duration of the catalyst pre-treatment (wet etching time, dry etching time and ball milling) on the diameter of CNTs. The synthesized CNTs samples were characterized by scanning and transmission electron microscopy and Raman spectroscopy. Wet etching (2M hydrofluoric acid) time was varied from 1 to 2.5 hrs and the diameter range was found to be in the range of 23 to 52 nm. The diameter range for CNTs produced for 3 hrs and 5 hrs of dry etching treatment (with ammonia gas) are 38 to 51 nm and 23 to 48 nm, respectively. The diameter size of CNTs produced using Ni (14 to 25 nm) was found to be smaller than Fe (38 to 51 nm). There is a significant decrease in the diameter of CNTs by prolonging the wet etching period. Shorter and curly shaped CNTs can also be obtained by using Ni as the catalyst. Keywords: chemical vapor deposition, carbon nanotubes, catalyst pretreatment

scholarly journals Dry Etching of Germanium with Laser Induced Reactive Micro Plasma

2021 ◽  
Author(s):  
Martin Ehrhardt ◽  
Pierre Lorenz ◽  
Jens Bauer ◽  
Robert Heinke ◽  
Mohammad Afaque Hossain ◽  
...  
Keyword(s):  
Ion Beam ◽  
Etching Rate ◽  
Dry Etching ◽  
Etching Process ◽  
High Tech ◽  
Etching Time ◽  
High Quality ◽  
Machined Surface ◽  
Reactive Plasma ◽  
New Processing

AbstractHigh-quality, ultra-precise processing of surfaces is of high importance for high-tech industry and requires a good depth control of processing, a low roughness of the machined surface and as little as possible surface and subsurface damage but cannot be realized by laser ablation processes. Contrary, electron/ion beam, plasma processes and dry etching are utilized in microelectronics, optics and photonics. Here, we have demonstrated a laser-induced plasma (LIP) etching of single crystalline germanium by an optically pumped reactive plasma, resulting in high quality etching. A Ti:Sapphire laser (λ = 775 nm, EPulse/max. = 1 mJ, t = 150 fs, frep. = 1 kHz) has been used, after focusing with a 60 mm lens, for igniting a temporary plasma in a CF4/O2 gas at near atmospheric pressure. Typical etching rate of approximately ~ 100 nm / min and a surface roughness of less than 11 nm rms were found. The etching results were studied in dependence on laser pulse energy, etching time, and plasma – surface distance. The mechanism of the etching process is expected to be of chemical nature by the formation of volatile products from the chemical reaction of laser plasma activated species with the germanium surface. This proposed laser etching process can provide new processing capabilities of materials for ultra—high precision laser machining of semiconducting materials as can applied for infrared optics machining.

Few-Layered MoS2 Nanoparticles Loaded TiO2 Nanosheets with Exposed {001} Facets for Enhanced Photocatalytic Activity

NANO ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. 1850129 ◽  
Author(s):  
Chujun Chen ◽  
Xia Xin ◽  
Jinniu Zhang ◽  
Gang Li ◽  
Yafeng Zhang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Charge Carrier ◽  
Visible Light ◽  
Recombination Rate ◽  
Active Species ◽  
Molar Ratio ◽  
Carrier Recombination ◽  
Tio2 Nanosheets ◽  
Photocatalytic Activities ◽  
Charge Carrier Recombination

To improve the high charge carrier recombination rate and low visible light absorption of {001} facets exposed TiO2 [TiO2(001)] nanosheets, few-layered MoS2 nanoparticles were loaded on the surfaces of TiO2(001) nanosheets by a simple photodeposition method. The photocatalytic activities towards Rhodamine B (RhB) were investigated. The results showed that the MoS2–TiO2(001) nanocomposites exhibited much enhanced photocatalytic activities compared with the pure TiO2(001) nanosheets. At an optimal Mo/Ti molar ratio of 25%, the MoS2–TiO2(001) nanocomposites displayed the highest photocatalytic activity, which took only 30[Formula: see text]min to degrade 50[Formula: see text]mL of RhB (50[Formula: see text]mg/L). The active species in the degradation reaction were determined to be h[Formula: see text] and [Formula: see text]OH according to the free radical trapping experiments. The reduced charge carrier recombination rate, enhanced visible light utilization and increased surface areas contributed to the enhanced photocatalytic performances of the 25% MoS2–TiO2(001) nanocomposites.

Synthesis of Silicon Nanowire Arrays by Metal-Assisted Chemical Etching in Aqueous NH4HF2 Solution

2012 ◽  
Vol 21 ◽  
pp. 109-115 ◽  
Author(s):  
S. Naama ◽  
T. Hadjersi ◽  
G. Nezzal ◽  
L. Guerbous
Keyword(s):  
Silicon Nanowires ◽  
Chemical Etching ◽  
Silicon Nanowire ◽  
Nanowire Arrays ◽  
Etching Time ◽  
Silicon Nanowire Arrays ◽  
Peak Intensity ◽  
One Step ◽  
Etching Parameters ◽  
P Type

One-step metal-assisted electroless chemical etching of p-type silicon substrate in NH4HF2/AgNO3 solution was investigated. The effect of different etching parameters including etching time, temperature, AgNO3 concentration and NH4HF2 concentration were investigated. The etched layers formed were investigated by scanning electron microscopy (SEM) and Photoluminescence. It was found that the etched layer was formed by well-aligned silicon nanowires. It is noted that their density and length strongly depend on etching parameters. Room temperature photoluminescence (PL) from etched layer was observed. It was observed that PL peak intensity increases significantly with AgNO3 concentration.

A Janus MoSSe monolayer: a potential wide solar-spectrum water-splitting photocatalyst with a low carrier recombination rate

2018 ◽  
Vol 6 (5) ◽  
pp. 2295-2301 ◽  
Author(s):  
Xiangchao Ma ◽  
Xin Wu ◽  
Haoda Wang ◽  
Yucheng Wang
Keyword(s):  
Water Splitting ◽  
Recombination Rate ◽  
Solar Spectrum ◽  
Carrier Recombination

A Janus MoSSe monolayer is theoretically predicted to be a wide solar-spectrum water-splitting photocatalyst with a low carrier recombination rate.

Influence of Etching Time on Surface Structural Properties of p- and n- Type Porous Silicon Nanostructures by Photo-Electrochemical Anodic Etching

2012 ◽  
Vol 576 ◽  
pp. 511-515
Author(s):  
N.A. Asli ◽  
Maslihan Ain Zubaidah ◽  
S.F.M. Yusop ◽  
Khairunnadim Ahmad Sekak ◽  
Mohammad Rusop ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Crystalline Silicon ◽  
Surface Characteristic ◽  
Electrochemical Anodization ◽  
Silicon Nanostructures ◽  
Etching Time ◽  
Force Microscopy ◽  
Etching Parameters ◽  
P Type ◽  
Substrate Doping

Porous silicon nanostructures (PSiN) are nanoporous materials which consist of uniform network of interconnected pore. The structure of PSiN is depending on etching parameters, including current density, HF electrolyte concentration, substrate doping type and level. In this work, the results of a structural p-type and n-type of porous silicon nanostructures were investigated by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM) is reported. Samples were prepared by photo-electrochemical anodization of p- and n-type crystalline silicon in HF electrolyte at different etching time. The surface morphology of PSiN was studied by FESEM with same magnification shown n-type surface form crack faster than p-type of PSiN. While the topography and roughness of PSiN was characterize by AFM. From topography shown the different etching time for both type PSiN produce different porosity and roughness respectively. There is good agreement between p- and n-type have different in terms of surface characteristic.

Dry Etching of GaN Using Reactive Ion Beam Etching and Chemically Assisted Reactive Ion Beam Etching

1997 ◽  
Vol 468 ◽  
Author(s):  
Jae-Won Lee ◽  
Hyong-Soo Park ◽  
Yong-Jo Park ◽  
Myong-Cheol Yoo ◽  
Tae-Il Kim ◽  
...  
Keyword(s):  
Room Temperature ◽  
Volume Fraction ◽  
Ion Beam ◽  
Etching Rate ◽  
Dry Etching ◽  
Ion Beam Etching ◽  
Etching Profile ◽  
Etching Parameters ◽  
Etching Selectivity ◽  
Reactive Ion Beam Etching

ABSTRACTDry etching characteristics of GaN using reactive ion beam etching (RIBE) were studied. Etching profile, etching rate and etching selectivity to a photoresist (PR) mask were investigated as a function of various etching parameters. Characteristics of chemically assisted reactive ion beam etching (CARIBE) and RIBE were compared at varied mixtures of CH4 and Cl2. A highly anisotropie etching profile with a smooth surface was obtained for tilted RIBE with Ch at room temperature. Etching selectivity to a PR was dramatically improved in RIBE and CARIBE when a volume fraction of CH4 to the mixture of CH4 and Ch was larger than 0.83.

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