Electron-beam-induced reactivation of Si dopants in hydrogenated GaAs: A minority carrier generation effect or an energetic electron excitation effect?

2000 ◽  
Vol 77 (20) ◽  
pp. 3206-3208 ◽  
Author(s):  
S. Silvestre ◽  
D. Bernard-Loridant ◽  
E. Constant ◽  
M. Constant ◽  
J. Chevallier
Keyword(s):  
Electron Beam ◽  
Minority Carrier ◽  
Energetic Electron ◽  
Electron Excitation ◽  
Generation Effect ◽  
Carrier Generation

Electron-beam-induced reactivation of Si dopants in hydrogenated and deuterated 2D AlGaAs heterostructures. Application to the fabrication of nanostructures

2002 ◽  
Vol 719 ◽  
Author(s):  
L. Kurowski ◽  
S. Silvestre ◽  
D. Loridant-Bernard ◽  
E. Constant ◽  
M. Barbe ◽  
...  
Keyword(s):  
Electron Beam ◽  
Energetic Electron ◽  
High Mobility ◽  
Surface States ◽  
Electron Excitation ◽  
High Electron ◽  
Electron Dose ◽  
Hydrogen Incorporation ◽  
Dose Threshold ◽  
Si Doped

AbstractHydrogen incorporation in n-type Si-doped GaAs epilayers is now a well-known process. This paper is devoted to the study of the stability of SiH (SiD) complexes when submitted to an electron beam in n-type Si-doped GaAs epilayer and also in 2D-AlGaAs heterostructures exposed to a hydrogen or deuterium plasma.The results obtained by Hall effect measurements on hydrogenated and deuterated GaAs epilayers with different thicknesses (0.2 and 0.35νm) and Si planar-doped AlGaAs/GaAs/InGaAs heterostructures exposed to an electron beam with different injection energies (10 to 50 keV) are presented. On one hand, the reactivation of Si dopants strongly decreases when deuterium is used. On the other hand, the study of this reactivation versus injection energies of electrons suggests an energetic electron excitation effect rather than a minority carrier generation effect. In addition, for the 0.2νm thick GaAs epilayer and the 2D heterostructures, the free carrier density does not vary significantly for low electron densities, and as a consequence, the reactivation of the Si dopants occurs above an electron dose threshold. This phenomenon might be attributed to the filling of surface states as the dopants are progressively reactivated.As a result, due to the electron dose threshold as well as their high electron mobility properties, Si planar-doped AlGaAs/GaAs/InGaAs heterostructures are particularly interesting to reactivate dopants, with a good spatial contrast, using an electron beam irradiation and the effects described in this paper could open the fabrication of high mobility 1D or 2D mesoscopic structures for electronic or optoelectronic applications.

Surface recombination effects on minority carrier diffusion length measurements using electron beam-induced current

1990 ◽  
Vol 48 (4) ◽  
pp. 744-745
Author(s):  
D.P. Malta ◽  
M.L. Timmons
Keyword(s):  
Electron Beam ◽  
Beam Energy ◽  
Minority Carrier ◽  
Diffusion Length ◽  
Effective Diffusion ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Logarithmic Scale ◽  
Minority Carrier Diffusion Length ◽  
Carrier Diffusion

Measurement of the minority carrier diffusion length (L) can be performed by measurement of the rate of decay of excess minority carriers with the distance (x) of an electron beam excitation source from a p-n junction or Schottky barrier junction perpendicular to the surface in an SEM. In an ideal case, the decay is exponential according to the equation, I = Ioexp(−x/L), where I is the current measured at x and Io is the maximum current measured at x=0. L can be obtained from the slope of the straight line when plotted on a semi-logarithmic scale. In reality, carriers recombine not only in the bulk but at the surface as well. The result is a non-exponential decay or a sublinear semi-logarithmic plot. The effective diffusion length (Leff) measured is shorter than the actual value. Some improvement in accuracy can be obtained by increasing the beam-energy, thereby increasing the penetration depth and reducing the percentage of carriers reaching the surface. For materials known to have a high surface recombination velocity s (cm/sec) such as GaAs and its alloys, increasing the beam energy is insufficient. Furthermore, one may find an upper limit on beam energy as the diameter of the signal generation volume approaches the device dimensions.

The Parameter Influence of Electron Beam Irradiation on GaN Based Blue LED

2011 ◽  
Vol 415-417 ◽  
pp. 2093-2096
Author(s):  
Zhi Guo Peng ◽  
Hai Lang Liu ◽  
Rui Bin Zhang
Keyword(s):  
Electron Beam ◽  
Electron Beam Irradiation ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Experimental Result ◽  
Beam Irradiation ◽  
Optical Efficiency ◽  
Blue Led ◽  
Low Energy Electron

Making use of the low energy electron beam produced by the accelerator of Dynamitron which has 1-3 Mev energy and 90KW maximum power, GaN based blue LED is proceed by the electron beam irradiation. The color and luminosity parameter of the irradiated LED are contrasted with the unirradiated LED. The experimental result is analyzed and discussed. The results show that the dominant wavelength is shifted, the color purity is improved, the flux and the optical efficiency are dreased by the electron beam irradiation. We also find that the displacement of atoms in LED quantum well, the non-complex compound and minority carrier lifetime is reduced by the electron beam irradiation.

Table-top Cathodoluminescence Microscopy for Geology

2020 ◽  
Author(s):  
Toon Coenen ◽  
Albert Polman
Keyword(s):  
Electron Beam ◽  
Detection System ◽  
Energetic Electron ◽  
Numerical Aperture ◽  
Graded Index ◽  
Thermo Fisher Scientific ◽  
Deformation Features ◽  
Backscattered Electron ◽  
User Friendly ◽  
Fisher Scientific

<p>Cathodoluminescence (CL) microscopy is a well-known technique for imaging geological specimens, in which the light that is generated with an energetic electron beam is collected and analyzed with a CL detector. CL provides a unique imaging contrast that can be used for visualizing growth zonation, distinguishing cement and granular detrital material, detecting trace elements, and characterizing fractures and deformation features in a large range of rocks, to name a few examples. In its simplest form CL imaging is performed with a static electron beam in an optical microscopy system (optical CL) but for more advanced experiments CL imaging is performed in a scanning electron microscope (SEM). This enables high scan speeds, high spatial resolution (< 100 nm), and correlation with other SEM based techniques such as X-ray imaging (EDS), secondary electron (SE) and backscattered electron (BSE) imaging, and more.</p><p>Currently, SEM-based CL work is mostly performed on costly floor model SEMs that require large amounts of space, complex auxiliary support systems, and an experienced operator to run the machine. In contrast, compact, affordable, and user-friendly table-top SEMs have improved substantially in the last years but they typically lack (advanced) CL imaging capabilities. Here, we will present our progress in developing a table-top SEM based CL system that can be used for geological research amongst other applications.</p><p>In particular, we have integrated a CL collection and detection system in a Thermo Fisher Scientific/Phenom XL table-top microscope, which already is equipped with SE, BSE, and EDS imaging modalities. In this SEM, electron energies of 5 – 15 keV can be used which is appropriate for most CL imaging experiments. The CL is collected using a multimode fiber optic cable connected with a graded index lens to increase the numerical aperture of the collection. Subsequently, the light is send to a spectrometer where the CL emission spectrum can be measured for every excitation point on the sample; a technique known as hyperspectral CL  imaging. To synchronize electron beam scanning with data acquisition and for data analysis we have developed dedicated software control.</p><p>We assess the potential of table-top CL by imaging representative polished zircon and quartz samples for various beam and acquisition parameters. To benchmark the system performance we compare our experimental results with results obtained from a state-of-the-art floor model SEM (Thermo Fisher Scientific Quanta 650 SFEG) system equipped with a high-end Delmic SPARC CL system. In the future, these developments may lower the threshold for using CL imaging through cost reduction and workflow simplification, making it accessible to a larger range of users within the field of geology and beyond.</p>

Sign in / Sign up

Export Citation Format

Share Document