Intraband Absorption in P-Type InGaAs at FIR Frequencies

1993 ◽  
Vol 329 ◽  
Author(s):  
Xiangkun Zhang ◽  
Phengpiao Liao ◽  
Ali Afzali-Kushaa ◽  
George I. Haddad
Keyword(s):  
Absorption Coefficient ◽  
Doping Concentration ◽  
Heavy Hole ◽  
Incident Radiation ◽  
Intraband Absorption ◽  
Valence Bands ◽  
P Type

AbstractIntraband absorption in p-type In.53Ga.47 As has been measured at FIR frequencies (40–240 cm−1). It is found that the absorption in p-type InGaAs, which is associated with transitions between the light- and heavy-hole valence bands, is very strong. The absorption coefficient is as high as 103–104 cm−1. It increases with the doping concentration but decreases with the frequency of the incident radiation and temperature.

High thermoelectric efficiency in co-doped degenerate p-type PbTe

2010 ◽  
Vol 1267 ◽  
Author(s):  
Ioannis Androulakis ◽  
Ilyia Todorov ◽  
Duck Young Chung ◽  
Sedat Ballikaya ◽  
Guoyu Wang ◽  
...  
Keyword(s):  
Heavy Hole ◽  
Elevated Temperatures ◽  
Resonant State ◽  
Band Model ◽  
Hole Density ◽  
Thermoelectric Efficiency ◽  
Na Substitution ◽  
Valence Bands ◽  
P Type ◽  
Two Band Model

AbstractWe explored the effect of K and K-Na substitution for Pb atoms in the lattice of PbTe, in an effort to test a hypothesis for the development of a resonant state that may enhance the thermoelectric power. At 300K the data can adequately be explained by a combination of a single and two-band model for the valence band of PbTe depending on hole density that varies in the range 1-15 × 1019 cm-3. A change in scattering mechanism was observed in the temperature dependence of the electrical conductivity, σ, for samples concurrently doped with K and Na which results in significantly enhanced σ at elevated temperatures and hence power factors. Thermal conductivity data provide evidence of a strong interaction between the light- and the heavy-hole valence bands at least up to 500K. Figure of merits as high as 1.3 at 700K were measured as a result of the enhanced power factors.

Valence band engineering and thermoelectric performance optimization in SnTe by Mn-alloying via a zone-melting method

2015 ◽  
Vol 3 (39) ◽  
pp. 19974-19979 ◽  
Author(s):  
Jun He ◽  
Xiaojian Tan ◽  
Jingtao Xu ◽  
Guo-Qiang Liu ◽  
Hezhu Shao ◽  
...  
Keyword(s):  
Seebeck Coefficient ◽  
Band Gap ◽  
Performance Optimization ◽  
Heavy Hole ◽  
Zone Melting ◽  
Energy Separation ◽  
Melting Method ◽  
Band Engineering ◽  
Valence Bands ◽  
P Type

Mn alloying in SnTe increases the band gap and decreases the energy separation between the light and heavy hole valence bands, leading to a significant enhancement in the Seebeck coefficient. The maximum ZT of ~1.25 is found at 920 K for p-type SnMn0.07Te.

scholarly journals Optimization of Sb2S3 Nanocrystal Concentrations in P3HT: PCBM Layers to Improve the Performance of Polymer Solar Cells

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2152
Author(s):  
E. M. Mkawi ◽  
Y. Al-Hadeethi ◽  
R. S. Bazuhair ◽  
A. S. Yousef ◽  
E. Shalaan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Doping Concentration ◽  
Polymer Solar Cells ◽  
Energy Levels ◽  
Acid Methyl Ester ◽  
Visible Absorption ◽  
Block Polymer ◽  
Coating Method ◽  
Electronic Parameters ◽  
P Type

In this study, polymer solar cells were synthesized by adding Sb2S3 nanocrystals (NCs) to thin blended films with polymer poly(3-hexylthiophene)(P3HT) and [6,6]-phenyl-C61-butyric-acid-methyl-ester (PCBM) as the p-type material prepared via the spin-coating method. The purpose of this study is to investigate the dependence of polymer solar cells’ performance on the concentration of Sb2S3 nanocrystals. The effect of the Sb2S3 nanocrystal concentrations (0.01, 0.02, 0.03, and 0.04 mg/mL) in the polymer’s active layer was determined using different characterization techniques. X-ray diffraction (XRD) displayed doped ratio dependences of P3HT crystallite orientations of P3HT crystallites inside a block polymer film. Introducing Sb2S3 NCs increased the light harvesting and regulated the energy levels, improving the electronic parameters. Considerable photoluminescence quenching was observed due to additional excited electron pathways through the Sb2S3 NCs. A UV–visible absorption spectra measurement showed the relationship between the optoelectronic properties and improved surface morphology, and this enhancement was detected by a red shift in the absorption spectrum. The absorber layer’s doping concentration played a definitive role in improving the device’s performance. Using a 0.04 mg/mL doping concentration, a solar cell device with a glass /ITO/PEDOT:PSS/P3HT-PCBM: Sb2S3:NC/MoO3/Ag structure achieved a maximum power conversion efficiency of 2.72%. These Sb2S3 NCs obtained by solvothermal fabrication blended with a P3HT: PCBM polymer, would pave the way for a more effective design of organic photovoltaic devices.

The Effect of Doping Concentration and Conductivity Type on Preferential Etching of 4H-SiC by Molten KOH

2004 ◽  
Vol 815 ◽  
Author(s):  
Ying Gao ◽  
Zehong Zhang ◽  
Robert Bondokov ◽  
Stanislav Soloviev ◽  
Tangali Sudarshan
Keyword(s):  
Thermal Diffusion ◽  
Basal Plane ◽  
Doping Concentration ◽  
Structural Defects ◽  
Etch Pits ◽  
Conductivity Type ◽  
Isotropic Etching ◽  
Electrochemical Processes ◽  
P Type ◽  
Koh Etching

AbstractMolten KOH etchings were implemented to delineate structural defects in the n- and ptype 4H-SiC samples with different doping concentrations. It was observed that the etch preference is significantly influenced by both the doping concentrations and the conductivity types. The p-type Si-face 4H-SiC substrate has the most preferential etching property, while it is least for n+ samples. It has been clearly demonstrated that the molten KOH etching process involves both chemical and electrochemical processes, during which isotropic etching and preferential etching are competitive. The n+ 4H-SiC substrate was overcompensated via thermal diffusion of boron to p-type and followed by molten KOH etching. Three kinds of etch pits corresponding to threading screw, threading edge, and basal plane dislocations are distinguishably revealed. The same approach was also successfully employed in delineating structural defects in (0001) C-face SiC wafers.

Light-induced absorption and optical damage in Sc-, Mg-, and Zn-doped near-stoichiometric LiNbO3

2018 ◽  
Vol 27 (03) ◽  
pp. 1850030 ◽  
Author(s):  
Junsheng Li ◽  
Youwen Liu ◽  
Huijie Zhang ◽  
Liangzun Tang ◽  
Chongjun He
Keyword(s):  
Steady State ◽  
Lithium Niobate ◽  
Absorption Coefficient ◽  
Ultraviolet Light ◽  
Infrared Absorption ◽  
Doping Level ◽  
Doping Concentration ◽  
Weak Absorption ◽  
Induced Absorption ◽  
Infrared Absorption Spectra

By measuring the ultraviolet-light-induced absorption in Sc-, Mg- and Zn-doped near-stoichiometric lithium niobate (LiNbO[Formula: see text], we find that the steady-state ultraviolet-light-induced absorption coefficient changes with respect to the doping concentration. There is a strong ultraviolet-light-induced absorption when doping concentration is below its photorefractive threshold and a really weak absorption when the crystal is highly doped. We also use OH[Formula: see text] infrared absorption spectra and the transmitted light spot distortion method to verify the result. Thus, we can determine if the doping level in these doped near-stoichiometric LiNbO3 crystals is above or below their photorefractive threshold by measuring the ultraviolet-light-induced absorption.

scholarly journals Ground Plane Impact on Performance of Relaxed Ge FinFETs

2019 ◽  
Vol 14 (1) ◽  
pp. 1-6
Author(s):  
Alberto Vinícius Oliveira ◽  
Guilherme Vieira Gonçalves ◽  
Paula Ghedini Der Agopian ◽  
João Antonio Martino ◽  
Jérôme Mitard ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Computer Aided Design ◽  
Doping Concentration ◽  
Ground Plane ◽  
Subthreshold Swing ◽  
Voltage Variation ◽  
Electrostatic Coupling ◽  
P Type ◽  
Aided Design ◽  
Channel Region

The implementation of a barrier potential layer underneath the channel region, well known as Ground Plane (GP) implantation, and its influence on the performance of relaxed germanium pFinFET devices is investigated in this manuscript. This study aims to explain the fin width dependence of the threshold voltage from experimental data and evaluates the ground plane doping concentration and its depth influence on relaxed p-type channel germanium FinFET parameters, as threshold voltage, transconductance and subthreshold swing, through Technology Computer-Aided Design (TCAD) numerical simulations. The threshold voltage variation reaches up to 80 mV from the narrowest device to the widest one, considering the studied range of ground plane doping concentration. Concerning the subthreshold swing parameter, neither the GP doping concentration, nor its depth play a significant role since the electrostatic coupling is predominant.

Probe of the Band Structure of MBE Grown p-Type InMnAs at Ultrahigh Magnetic Fields

SPIN ◽  
2015 ◽  
Vol 05 (01) ◽  
pp. 1550002 ◽  
Author(s):  
Y. Sun ◽  
F. V. Kyrychenko ◽  
G. D. Sanders ◽  
C. J. Stanton ◽  
G. A. Khodaparast ◽  
...  
Keyword(s):  
Optical Properties ◽  
Magnetic Fields ◽  
Band Structure ◽  
Heavy Hole ◽  
Theoretical Calculations ◽  
Interaction Strength ◽  
Golden Rule ◽  
Exchange Interactions ◽  
Landau Levels ◽  
P Type

We present a theoretical and experimental study on electronic and magneto-optical properties of p-type paramagnetic InMnAs dilute magnetic semiconductor (DMS) alloys in ultrahigh (> 100 T) external magnetic fields (B). Theoretical calculations are based on an 8-band Pidgeon–Brown model which is generalized to include the wavevector dependence of the electronic states along B as well as s–d and p–d exchange interactions with localized Mn d-electrons. The spin-dependent electronic structure as a function of Mn doping is computed and the dependence of the valence band structure on parameters such as the sp–d exchange interaction strength and effective masses in paramagnetic p- InMnAs alloys are examined. The cyclotron resonance (CR) and magneto-optical properties of InMnAs are calculated using Fermi's golden rule. Two strong CR peaks are observed in p-type InMnAs alloys which correspond to the transitions within either heavy-hole (HH) or light-hole (LH) Landau levels. Furthermore, we also observed strong resonance absorption for electron-active polarization which can occur in p-type semiconductors originating from transitions between the light and heavy hole Landau levels.

Highly Doped P-Type, N-Type CdS Thin Films and Diodes

1993 ◽  
Vol 329 ◽  
Author(s):  
Wen P. Shen ◽  
Hoi S. Kwok
Keyword(s):  
Thin Films ◽  
Doping Concentration ◽  
Annealing Process ◽  
Laser Deposition ◽  
Post Annealing ◽  
Gaas Substrates ◽  
Cds Thin Film ◽  
Good Crystalline Quality ◽  
Cds Thin Films ◽  
P Type

AbstractCdS thin films with doping concentration as high as 1017 cm-3 for p-type or 1021 cm-3 for n-type were achieved by pulsed excimer laser deposition without any post-annealing process. These films were grown on InP or GaAs substrates with good crystalline quality. By using this technique, CdS thin film p-n junctions were produced successfully.

Strain effect on the intraband absorption coefficient for spherical CdSe/CdS/ZnSe core–shell–shell quantum dots

2022 ◽  
Vol 141 ◽  
pp. 106400
Author(s):  
K.A. Rodríguez-Magdaleno ◽  
R. Pérez-Álvarez ◽  
F. Ungan ◽  
J.C. Martínez-Orozco
Keyword(s):  
Quantum Dots ◽  
Absorption Coefficient ◽  
Strain Effect ◽  
Core Shell ◽  
Intraband Absorption
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