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Cu/Sb Codoping for Tuning Carrier Concentration and Thermoelectric Performance of GeTe-Based Alloys with Ultralow Lattice Thermal Conductivity
摘要： Pristine GeTe shows promising thermoelectric performance but is limited by the high carrier concentration (nH) from Ge vacancies and thermal conductivity. Herein, Cu/Sb was chosen as codopants to suppress the high nH and to decrease thermal conductivity. In this condition, a promising zT of ～1.62 under 773 K was acquired in the Ge0.85Te(CuSb)0.075 system proposed in this paper/work. Results show that as the dopant concentration increases, the power factor rises due to the reduction of the nH to ～1 × 1020 cm?3. Apart from this, the total thermal conductivity also declines from ～7.4 W m?1 K?1 to ～1.59 W m?1 K?1 originating from an ultralow lattice thermal conductivity, in which the multiscatter mechanism from grain boundaries and point defect disperses the frequency phonons di?erently. The ?ndings in this paper combine thermal and electronic strategies and lay the foundation to develop Pb-free thermoelectric materials.
关键词： multiscatter mechanism,Cu/Sb codoped GeTe,thermoelectric materials,ultralow lattice thermal conductivity,zT value,carrier concentration,Seebeck coefficient
更新于2025-11-14 17:03:37
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Enhancement in the efficiency of Sb2Se3 solar cells by adding low lattice mismatch CuSbSe2 hole transport layer
摘要： As an excellent light absorbing material, antimony selenide (Sb2Se3) has attracted researchers to explore its application in solar cells. At present, the e?ciency of Sb2Se3 solar cells is still too low because of the low carrier concentration and high back surface recombination. In this study, we prepared an additional CuSbSe2 ?lm as hole transport layer by co-sputtering Sb2Se3 and Cu targets. It reduced the surface roughness of the absorption layer and the back surface recombination, which was bene?cial to the collection of carriers. Due to the higher carrier concentration of CuSbSe2 ?lm and proper di?usion of Cu, the carrier concentration of the absorption layer is greatly improved, thereby e?ectively increasing the Voc of the Sb2Se3 thin ?lm solar cells. Finally, we obtained a 5.87% e?ciency for the FTO/CdS/Sb2Se3/CuSbSe2/Au solar cell, which is more than 25% higher than the basic e?ciency.
关键词： Carrier concentration,CuSbSe2,Co-sputtering,Sb2Se3,Lattice mismatch
更新于2025-09-23 15:19:57
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Copper doping of Sb2S3: fabrication, properties, and photovoltaic application
摘要： Sb2S3 solar cells are lagging behind conventional thin-film solar cells such as silicon solar cells and cadmium telluride solar cells in the power conversion efficiency (PCE). One of the most prominent problems is that the carrier concentration of Sb2S3 is relatively low. In order to increase the carrier concentration, elemental Cu was doped into Sb2S3 film by radio-frequency (RF) magnetron sputtering. We proved that Cu was doped into Sb2S3 films and mainly anchored with sulfur in the form of copper chalcogenide species at the surface and grain boundaries of Sb2S3. The doping of Cu essentially affects the physical and electrical properties of RF-sputtered Sb2S3 films such as the optical band gap, crystallinity, chemical composition, morphology, and carrier concentration. Specially, the electronic carrier concentration is remarkably increased from 6.28 × 109 to 6.06 × 1010 cm?3 and the Fermi level is also significantly uplifted after prudent doping with Cu. Planar solar cells based on RF-sputtered Cu-doped Sb2S3 absorber deliver an increased PCE of 1.13% and show good stability. This research proves that doping of Cu is an alternative and effective way to improve the electronic property of Sb2S3 films and enhance the performance of Sb2S3 solar cells.
关键词： RF magnetron sputtering,Cu-doping,photovoltaic application,carrier concentration,Sb2S3 solar cells
更新于2025-09-16 10:30:52
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Visualization of different carrier concentrations in n-type-GaN semiconductors by phase-shifting electron holography with multiple electron biprisms
摘要： Phase-shifting electron holography (PS-EH) using a transmission electron microscope (TEM) was applied to visualize layers with different concentrations of carriers activated by Si (at dopant levels of 1019, 1018, 1017 and 1016 atoms cm?3) in n-type GaN semiconductors. To precisely measure the reconstructed phase pro?les in the GaN sample, three electron biprisms were used to obtain a series of high-contrast holograms without Fresnel fringes generated by a biprism ?lament, and a cryo-focused-ion-beam (cryo-FIB) was used to prepare a uniform TEM sample with less distortion in the wide ?eld of view. All layers in a 350-nm-thick TEM sample were distinguished with 1.8-nm spatial resolution and 0.02-rad phase-resolution, and variations of step width in the phase pro?le (corresponding to depletion width) at the interfaces between the layers were also measured. Thicknesses of the active and inactive layers at each dopant level were estimated from the observed phase pro?le and the simulation of theoretical band structure. Ratio of active-layer thickness to total thickness of the TEM sample signi?cantly decreased as dopant concentration decreased; thus, a thicker TEM sample is necessary to visualize lower carrier concentrations; for example, to distinguish layers with dopant concentrations of 1016 and 1015 atoms cm?3. It was estimated that sample thickness must be more than 700 nm to make it be possible to detect sub-layers by the combination of PS-EH and cryo-FIB.
关键词： phase-shifting electron holography,dopant pro?ling,carrier concentration,GaN,inactive layer,active layer
更新于2025-09-16 10:30:52
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Simulation study to find suitable dopants of CdS buffer layer for CZTS solar cell
摘要： The performance of CZTS solar cell, a promising candidate in the field of energy production from sunlight, can be improved by optimizing the parameters of most widely used CdS buffer layer. In this work, numerical study have been done on the typical CZTS solar cell structures containing Mo thin film as back contact on glass substrate using SCAPS-1D solar cell simulation software. Then, the CZTS has been used as the absorber layer followed by CdS buffer later. Following, ZnO and transparent conducting oxide n-ITO layers have been considered as window layer and front contact, respectively. In the simulations, the CdS buffer layer has been doped with three different materials such as Silver (Ag), Copper (Cu) and Chlorine (Cl) for a wide acceptable range of carrier concentration. After obtaining the suitable carrier concentration, the thickness of the doped buffer layer has been varied keeping other layer parameters constant to see the variation of performance parameters open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF) and efficiency (η) of the CZTS solar cell.
关键词： SCAPS-1D,Solar cell,CZTS,Doped CdS,Carrier concentration
更新于2025-09-12 10:27:22
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Empirical modeling of dopability in diamond-like semiconductors
摘要： Carrier concentration optimization has been an enduring challenge when developing newly discovered semiconductors for applications (e.g., thermoelectrics, transparent conductors, photovoltaics). This barrier has been particularly pernicious in the realm of high-throughput property prediction, where the carrier concentration is often assumed to be a free parameter and the limits are not predicted due to the high computational cost. In this work, we explore the application of machine learning for high-throughput carrier concentration range prediction. Bounding the model within diamond-like semiconductors, the learning set was developed from experimental carrier concentration data on 127 compounds ranging from unary to quaternary. The data were analyzed using various statistical and machine learning methods. Accurate predictions of carrier concentration ranges in diamond-like semiconductors are made within approximately one order of magnitude on average across both p- and n-type dopability. The model fit to empirical data is analyzed to understand what drives trends in carrier concentration and compared with previous computational efforts. Finally, dopability predictions from this model are combined with high-throughput quality factor predictions to identify promising thermoelectric materials.
关键词： dopability,machine learning,diamond-like semiconductors,thermoelectrics,carrier concentration
更新于2025-09-04 15:30:14