scholarly journals Improved InGaAs and InGaAs/InAlAs Photoconductive Antennas Based on (111)-Oriented Substrates

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 495 ◽  
Author(s):  
Kirill Kuznetsov ◽  
Aleksey Klochkov ◽  
Andrey Leontyev ◽  
Evgeniy Klimov ◽  
Sergey Pushkarev ◽  
...  
Keyword(s):  
Radiation Power ◽  
Terahertz Wave ◽  
Terahertz Time Domain Spectroscopy ◽  
Pump Probe ◽  
Substrate Orientation ◽  
Photoconductive Antennas ◽  
Transmission Geometry ◽  
Hall Effect Measurements ◽  
Inp Substrates ◽  
Probe Measurements

The terahertz wave generation by spiral photoconductive antennas fabricated on low-temperature In0.5Ga0.5As films and In0.5Ga0.5As/In0.5Al0.5As superlattices is studied by the terahertz time-domain spectroscopy method. The structures were obtained by molecular beam epitaxy on GaAs and InP substrates with surface crystallographic orientations of (100) and (111)A. The pump-probe measurements in the transmission geometry and Hall effect measurements are used to characterize the properties of LT-InGaAs and LT-InGaAs/InAlAs structures. It is found that the terahertz radiation power is almost four times higher for LT-InGaAs samples with the (111)A substrate orientation as compared to (100). Adding of LT-InAlAs layers into the structure with (111)A substrate orientation results in two orders of magnitude increase of the structure resistivity. The possibility of creating LT-InGaAs/InAlAs-based photoconductive antennas with high dark resistance without compensating Be doping is demonstrated.

Pump-Probe Measurements Using Silicon Nanocrystal Waveguides

2003 ◽  
Vol 770 ◽  
Author(s):  
Nathanael Smith ◽  
Max J. Lederer ◽  
Marek Samoc ◽  
Barry Luther-Davies ◽  
Robert G. Elliman
Keyword(s):  
Probe Beam ◽  
Time Resolution ◽  
Pump Beam ◽  
Silicon Nanocrystals ◽  
Continuous Wave ◽  
Optical Gain ◽  
Optical Pump ◽  
Time Resolved ◽  
Pump Probe ◽  
Probe Measurements

AbstractOptical pump-probe measurements were performed on planar slab waveguides containing silicon nanocrystals in an attempt to measure optical gain from photo-excited silicon nanocrystals. Two experiments were performed, one with a continuous-wave probe beam and a pulsed pump beam, giving a time resolution of approximately 25 ns, and the other with a pulsed pump and probe beam, giving a time resolution of approximately 10 ps. In both cases the intensity of the probe beam was found to be attenuated by the pump beam, with the attenuation increasing monotonically with increasing pump power. Time-resolved measurements using the first experimental arrangement showed that the probe signal recovered its initial intensity on a time scale of 45-70 μs, a value comparable to the exciton lifetime in Si nanocrystals. These data are shown to be consistent with an induced absorption process such as confined carrier absorption. No evidence for optical gain was observed.

scholarly journals Giant Photoluminescence Enhancement and Carrier Dynamics in MoS2 Bilayers with Anomalous Interlayer Coupling

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1994
Author(s):  
Han Li ◽  
Yating Ma ◽  
Zhongjie Xu ◽  
Xiang’ai Cheng ◽  
Tian Jiang
Keyword(s):  
Optical Properties ◽  
Transition Metal Dichalcogenides ◽  
Interlayer Coupling ◽  
Carrier Dynamics ◽  
Probe Signal ◽  
Exciton Resonance ◽  
Pump Probe ◽  
Metal Dichalcogenides ◽  
Photoluminescence Enhancement ◽  
Probe Measurements

Fundamental researches and explorations based on transition metal dichalcogenides (TMDCs) mainly focus on their monolayer counterparts, where optical densities are limited owing to the atomic monolayer thickness. Photoluminescence (PL) yield in bilayer TMDCs is much suppressed owing to indirect-bandgap properties. Here, optical properties are explored in artificially twisted bilayers of molybdenum disulfide (MoS2). Anomalous interlayer coupling and resultant giant PL enhancement are firstly observed in MoS2 bilayers, related to the suspension of the top layer material and independent of twisted angle. Moreover, carrier dynamics in MoS2 bilayers with anomalous interlayer coupling are revealed with pump-probe measurements, and the secondary rising behavior in pump-probe signal of B-exciton resonance, originating from valley depolarization of A-exciton, is firstly reported and discussed in this work. These results lay the groundwork for future advancement and applications beyond TMDCs monolayers.

Coherent coupling effects in pump–probe measurements with collinear, copropagating beams

1984 ◽  
Vol 9 (8) ◽  
pp. 359 ◽  
Author(s):  
T. F. Heinz ◽  
K. B. Eisenthal ◽  
S. L. Palfrey
Keyword(s):  
Coupling Effects ◽  
Pump Probe ◽  
Coherent Coupling ◽  
Probe Measurements

The effect of substrate orientation on the morphology of InAs nanostructures on (001) and (11n)A/B (n=1–5) InP substrates

2000 ◽  
Vol 218 (2-4) ◽  
pp. 203-208
Author(s):  
Zhongzhe Sun ◽  
Ju Wu ◽  
Yonghai Chen ◽  
Fengqi Liu ◽  
Ding Ding ◽  
...  
Keyword(s):  
Substrate Orientation ◽  
Inp Substrates

Impact of rapid thermal annealing and hydrogenation on the doping concentration and carrier mobility in solid phase crystallized poly-Si thin films

2011 ◽  
Vol 1321 ◽  
Author(s):  
A. Kumar ◽  
P.I. Widenborg ◽  
H. Hidayat ◽  
Qiu Zixuan ◽  
A.G. Aberle
Keyword(s):  
Thin Films ◽  
Electronic Properties ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Carrier Mobility ◽  
Crystalline Silicon ◽  
Solid Phase ◽  
Dopant Activation ◽  
Hall Effect Measurements ◽  
Probe Measurements

ABSTRACTThe effect of the rapid thermal annealing (RTA) and hydrogenation step on the electronic properties of the n+ and p+ solid phase crystallized (SPC) poly-crystalline silicon (poly-Si) thin films was investigated using Hall effect measurements and four-point-probe measurements. Both the RTA and hydrogenation step were found to affect the electronic properties of doped poly-Si thin films. The RTA step was found to have the largest impact on the dopant activation and majority carrier mobility of the p+ SPC poly-Si thin films. A very high Hall mobility of 71 cm2/Vs for n+ poly-Si and 35 cm2/Vs for p+ poly-Si at the carrier concentration of 2×1019 cm-3 and 4.5×1019 cm-3, respectively, were obtained.

scholarly journals Боковой перенос энергии при возбуждении плазмонов терагерцовой волной в периодической пространственно несимметричной графеновой структуре

2019 ◽  
Vol 53 (9) ◽  
pp. 1189
Author(s):  
Д.В. Фатеев ◽  
К.В. Машинский ◽  
И.М. Моисеенко ◽  
В.В. Попов
Keyword(s):  
Incident Wave ◽  
Radiation Power ◽  
Power Conversion ◽  
Incident Radiation ◽  
Terahertz Wave ◽  
Wave Power ◽  
Excitation Condition ◽  
Maximum Conversion

AbstractThe power conversion of a terahertz wave normally incident on a periodic graphene structure to propagating-plasmon power is theoretically studied. The conditions of the maximum conversion of the incident radiation power to the propagating-plasmon power and excitation condition of unidirectional traveling plasmon are determined. It is found that up to 15% of the incident wave power can be converted to propagating-plasmon power.

Properties of Bi and BiSb Nano-Dimensional Layers in Thz Frequency Range

2020 ◽  
Vol 312 ◽  
pp. 206-212
Author(s):  
Ivan L. Tkhorzhevskiy ◽  
Anton D. Zaitsev ◽  
Petr S. Demchenko ◽  
Dmitry V. Zykov ◽  
Aleksei V. Asach ◽  
...  
Keyword(s):  
Phase Shift ◽  
Time Domain ◽  
Terahertz Wave ◽  
Film Structure ◽  
Charge Carriers ◽  
Frequency Range ◽  
Terahertz Time Domain Spectroscopy ◽  
Antimony Content ◽  
Mobility Of Charge Carriers ◽  
Substrate Film

In the present paper we demonstrate and compare different properties of Bi and Bi1-xSbx thin films placed on polyimide (PI) substrate in frequency range from 0.2 to 1.0 THz. Bi films with a thickness of 40, 105 and 150 nm have been studied as well as 150 nm Bi1-xSbx solid solutions with Sb concentration of 5, 8, 12 and 15 %. An effective refractive index and permittivity of whole substrate/film structures have been derived by using terahertz time-domain spectroscopy (THz-TDS) method. These measurements have shown the positive phase shift in PI substrate with a thickness of 42 μm and revealed that it is barely transparent in studied frequency range, but the whole substrate/film structure provides the negative phase shift of terahertz wave. It was shown that the permittivity depends on mobility of charge carriers which is driven by film thickness and antimony content.

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