scholarly journals Femtosecond Probe-Probe Transmission Studies of Lt-Grown Gaas Near the Band Edge

1993 ◽  
Vol 325 ◽  
Author(s):  
H. B. Radousky ◽  
A. F. Bello ◽  
D. J. Erskine ◽  
L. N. Dinh ◽  
M. J. Bennahmias ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Band Edge ◽  
Gaas Film ◽  
Si Substrate ◽  
Gaas Sample ◽  
Free Standing ◽  
Pulse Technique ◽  
Probe Transmission ◽  
Transmission Measurements ◽  
Transmission Studies

AbstractWe have studied the near-edge optical response of a LT-grown GaAs sample which was deposited at 300 °C on a Si substrate, and then annealed at 600 °C. The Si was etched away to leave a 3-micron free standing GaAs film. Femtosecond transmission measurements were made using an equal pulse technique at four wavelengths between 825 and 870 nm. For each wavelength we observe both a multipicosecond relaxation time, as well as a shorter relaxation time which is less than 100 femtoseconds.

Contactless Spatially Resolved Measurement of Bulk Free-Carrier Lifetime in Silicon Ingots

1986 ◽  
Vol 69 ◽  
Author(s):  
S. M. Johnson ◽  
L. G. Johnson ◽  
R. Hemphill
Keyword(s):  
Spatial Dependence ◽  
Polycrystalline Silicon ◽  
Carrier Lifetime ◽  
Transient Absorption ◽  
Free Carrier ◽  
Large Area ◽  
Spatially Resolved ◽  
Probe Transmission ◽  
Transmission Measurements ◽  
Absorption Measurements

AbstractA contactless spatially resolved measurement of bulk free-carrier lifetime in polycrystalline silicon ingots was accomplished using optically modulated free-carrier infrared absorption. Using a CW Nd:YAG laser (λ = 1.319 μm) for a probe and novel pulsed, tunable, infrared dye laser (λ = 1.10 to 1.13 μm) with photon energies near the Si bandgap, for a pump, the free-carrier lifetime was determined from transient absorption measurements to a maximum depth of 3.0 cm from the surface of an ingot. The spatial dependence of the free-carrier lifetime and the distribution of precipitates (determined from infrared probe transmission measurements) measured along the growth axis of an ingot were found to be strongly related to the spatial dependence of the I–V characteristics of large area solar cells fabricated from the subsequently wafered ingot.

Optical and Electrical Characterizations of Nanoscale Robust 3C-SiC Membrane for UV Sensing Applications

2018 ◽  
Vol 775 ◽  
pp. 278-282
Author(s):  
A.R.M. Foisal ◽  
T. Dinh ◽  
A. Iacopi ◽  
L. Hold ◽  
E.W. Streed ◽  
...  
Keyword(s):  
Uv Light ◽  
Optical Characterization ◽  
Considerable Change ◽  
Electrical Contacts ◽  
Si Substrate ◽  
Uv Illumination ◽  
Sensing Applications ◽  
Transmission Measurements ◽  
Electrical Characterizations

This paper presents the fabrication and optical characterization of an ultrathin 3C-SiC membrane for UV light detection. SiC nanoscale film was grown on Si substrate and subsequently released to form a robust membrane with a high aspect ratio of about 5000. Transmission measurements were performed to determine the thickness of the film with a high accuracy of 98%. We also employed a simple and highly effective direct wirebonding technique to form electrical contacts to the SiC membrane. The considerable change in the photocurrent of the SiC membrane was observed under UV illumination, indicating the potential of using 3C-SiC membranes for UV detection.

GaAs film on Si substrate transplanted from GaAs/Ge structure by direct bonding

2003 ◽  
Vol 82 (22) ◽  
pp. 3892-3894 ◽  
Author(s):  
N. Chandrasekaran ◽  
T. Soga ◽  
T. Jimbo
Keyword(s):  
Gaas Film ◽  
Si Substrate

Effect of Layer Relaxation on the Internal Photoemission in Pt/Si1−xGex Schottky Barrier Type Infrared Detectors

1999 ◽  
Vol 607 ◽  
Author(s):  
B. Aslan ◽  
R. Turan ◽  
O. Nur ◽  
M. Karlsteen ◽  
M. Willander
Keyword(s):  
Barrier Height ◽  
Strain Relaxation ◽  
Infrared Detector ◽  
Band Edge ◽  
Schottky Junction ◽  
Si Substrate ◽  
Strained Si ◽  
Internal Photoemission ◽  
Schottky Type ◽  
P Type

AbstractA Schottky type infrared detector fabricated on a p-type Si1−xGex substrate has a higher cut-off wavelength than one on a pure Si substrate because the barrier height of the Schottky junction on p-type Si1−xGex decreases with the Ge content and the induced strain in the Si1−xGex layer. We have studied the effect of the strain relaxation on the internal photoemission and I-V characteristics of a Pt/Si1−xGex Schottky junction with x=0.14. It is shown that the cut-off wavelength of the diode made on a strained Si0.86Ge0.14 layer is higher than that on a Si substrate as expected. This shows the possibility of tuning the range of these detectors in the mid-infrared region. However, the thermal relaxation in the Si0.86Ge0.14 layer is found to reduce the cut-off wavelength to lower values, showing that the difference between the Fermi level of the metal and the valence band edge increases with the layer relaxation. This effect should be taken into account when a Schottky type infrared detector is manufactured on a strained Si1−xGex film. I-V characteristics of the junctions also indicate an increase of the barrier height with the relaxation of Si1−xGex. These results demonstrate the band edge movements in a Si ixGex layer experimentally agree with the expected changes in the band structure of the Si1−xGex layer with strain relaxation.

Optical Transmission Measurements on MOCVD Grown GaMnN Films on Sapphire

2006 ◽  
Vol 955 ◽  
Author(s):  
Fevzi Erdem Arkun ◽  
Nadia A El-Masry ◽  
John Muth ◽  
Xiyao Zhang ◽  
Amr Mahrouse ◽  
...  
Keyword(s):  
Absorption Band ◽  
Energy Band ◽  
Optical Transmission ◽  
Chemical Vapor ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Broad Absorption Band ◽  
Co Doping ◽  
Transmission Measurements ◽  
Mn Concentration

ABSTRACTWe demonstrate optical transmission measurements performed on 1.2 μm thick GaMnN films grown by metalorganic chemical vapor deposition on (0001) sapphire substrates. According to the data acquired from these measurements, Mn forms a deep acceptor band at 1.4 eV above the valance band of GaMnN. Full width at half maximum of this absorption band increases from 107 meV to 198meV as the Mn concentration increases from 0.3% to 1.6 %; which indicates that this band becomes wider as the concentration of Mn increases in the lattice. A broad absorption band starting at 1.9eV and extending to the band edge of GaMnN was also determined. This was attributed to the transition from the Mn energy band to the conduction band edge of GaMnN. Absorption at both of these bands scales with the Mn concentration and thickness of the films. The effect of co-doping of GaMnN films with magnesium on the transmission spectra was also investigated. The absorption band initially observed at 1.4 eV was shifted to 1.6 eV as a result of introduction of Magnesium into the lattice of GaMnN. From these results we conclude that Mn is incorporated in the lattice and forms an energy band in the bandgap of GaMnN. The width of this energy band is also a function of the Mn concentration in GaMnN.

Measurements of Melting Velocities in Gold Films on a Picosecond Time Scale

1992 ◽  
Vol 279 ◽  
Author(s):  
B. E. Homan ◽  
M. T. Connery ◽  
D. E. Harrison ◽  
C. A. Macdonald
Keyword(s):  
Direct Measurement ◽  
Time Scale ◽  
Dye Laser ◽  
Gold Films ◽  
Interfacial Velocity ◽  
Pump Probe ◽  
Laser Probe ◽  
Picosecond Time Scale ◽  
Probe Transmission ◽  
Transmission Measurements

ABSTRACTMelting velocities were measured in thin gold films by performing pump/probe transmission measurements using a unique picosecond excimer pump and dye laser probe. Monitoring the depth of the liquid by changes in the near psuedo-Brewster's angle transmission allowed for direct measurement of crystal/melt interfacial velocity up to 1500 m/s.

Very-low-threshold photonic band-edge lasers from free-standing triangular photonic crystal slabs

2002 ◽  
Vol 80 (19) ◽  
pp. 3476-3478 ◽  
Author(s):  
Han-Youl Ryu ◽  
Soon-Hong Kwon ◽  
Yong-Jae Lee ◽  
Yong-Hee Lee ◽  
Jeong-Soo Kim
Keyword(s):  
Photonic Crystal ◽  
Band Edge ◽  
Free Standing ◽  
Photonic Crystal Slabs ◽  
Low Threshold ◽  
Photonic Band
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