Enhanced Carrier Concentration Research Articles

Tailoring the Electronic Structures and Spectral Properties of ZnO with Irradiation Defects Generated Under Intense Electronic Excitation: A Combined Experimental and DFT Approach

AbstractThe relationship between the composition of the internal defect states, spectral properties, and correlated electronic structures of wurtzite zinc oxide (ZnO) crystals under 645 MeV Xe35+ irradiation is systematically investigated, employing experimental characterizations combined with first‐principle calculations. Based on the ion irradiation‐induced thermal expansion and relaxation processes, the high concentration of vacancy/interstitial defects produced from the transient disordered phase in molten track states trigger photoelectric changes, as follows: i) the generation of internal defect states effectively reduces the intrinsic bandgap (3.25 eV → 2.66 eV); ii) a large number of defective active sites inhibits the recombination between electron–hole pairs, causing dark conductance and photoconductance to increase with increasing damage levels until optimal fluence is achieved. Based on the density functional theory (DFT) with the GGA + U (GGA = generalized gradient approximation) method, the defective models associated with the different electronic structures, density of states, formation energy, and the nature of the chemical bonding are established. The narrowing of the bandgap observed experimentally and the enhancement of carrier concentration originating from the internal electron defect states are qualitatively verified, therefore laying the foundation for designing future nanoscale photoelectronic devices and microelectronics applications.

Low temperature (002)-oriented zinc oxide films prepared using ozone-based spatial atomic layer deposition

In this study, ZnO films are prepared at a low temperature of 150 °C by using spatial atomic layer deposition (sALD) with diethylzinc and ozone as precursor and oxidant. The ozone flow rate is varied to systematically investigate its effect on optical, structural and electrical properties. The experimental results show that the self-limiting surface reactions can occur at the low ozone flow rate of 200 sccm, confirming ALD growth mode. All the ozone flow rates lead to ZnO (002) crystalline orientation, which is difficult to be obtained for conventional water-based ALD ZnO films at the low temperature. The increased ozone flow rate results in an increased amount of oxygen vacancies, enhanced carrier concentration and a reduced stress. The resistivity and carrier concentration can be tuned in the range of 4.75–0.08 Ω-cm and (1.1–5.5) × 1018 cm−3. Finally, the sALD ZnO film on polyethylene terephthalate reveals a high stability in the film property against bending. This study is beneficial for the utilization of ZnO films in optoelectronic devices that demand the (002) preferred orientation, especially under low-temperature conditions.

Enhancement of thermoelectric properties in Sr0.7Ba0.3Nb2O6−δ-based ceramics via nano-sized Ti as additive

A series of Sr0.7Ba0.3Nb2O6−δ/x wt. % Ti (x = 1, 3, 5, and 10) composite ceramic thermoelectric materials were prepared, and the mechanism for improving their thermoelectric properties was explored. The experimental results demonstrate that nano-additive titanium powder undergoes oxidation to form TiO2 during sintering. However, under annealing in a reducing atmosphere, oxidation reactions further deplete the lattice oxygen, leading to an increased generation of oxygen vacancies and enhanced carrier concentration, ultimately leading to successful resistivity reduction. The samples consistently exhibit low thermal conductivity values below 2.0 W m−1 K−1 due to crystal defects, complex structure, and phonon scattering at the grain boundaries. The sample doped with 5 wt. %. Ti exhibits the lowest resistivity and highest PF value (409.3 μW/m K2 at 1073 K). Consequently, the figure of merit of Sr0.7Ba0.3Nb2O6−δ with 5 wt. % Ti attains its maximum value of 0.30 at 1073 K, representing a 50% increase compared to that of the undoped sample Sr0.7Ba0.3Nb2O6−δ (0.20 at 1073 K).

High Thermoelectric Power Factors in Plastic/Ductile Bulk SnSe2 -Based Crystals.

The recently discovered plastic/ductile inorganic thermoelectric (TE) materials open a new avenue for the fabrication of high-efficiently flexible TE devices, which can utilize the small temperature difference between human body and environment to generate electricity. However, the maximum power factor (PF) of current plastic/ductile TE materials is usually around or less than 10 µW cm-1 K-2 , much lower than the classic brittle TE materials. In this work, a record-high PF of 18.0 µW cm-1 K-2 at 375 K in plastic/ductile bulk SnSe2 -based crystals is reported, superior to all the plastic inorganic TE materials and flexible organic TE materials reported before. The origin of such high PF is from the modulation of material's stacking forms and polymorph crystal structures via simultaneously doping Cl/Br at Se-site and intercalating Cu inside the van der Waals gap, leading to the significantly enhanced carrier concentrations and mobilities. An in-plane fully flexible TE device made of the plastic/ductile SnSe2 -based crystals is successfully developed to show a record-high normalized maximum power density to 0.18W m-1 under a temperature difference of 30 K. This work indicates that the plastic/ductile material can realize high TE power factor to achieve large output electric power density in flexible TE technology.

Enhanced thermoelectric performance of iso-valent Al substituted Bi2S3via carrier tuning and multiscale phonon scattering

Bismuth sulphide is one of the promising thermoelectric material due to its low thermal conductivity, less toxicity, and abundance in nature. This work analyzed an Al-substituted Bi2S3 compounds for mid-temperature thermoelectric applications prepared by hydrothermal route. The combination of stacking faults and point defects significantly improved the phonon scattering, resulting in decreased thermal conductivity in (x = 0.10) Al substituted sample with the value of 0.498 Wm−1K−1 at 623 K. Also, it simultaneously contributes to the enhancement in carrier concentration of −2.15 × 1019 cm−3, resulting the increased electrical conductivity of 10,142 Sm-1 at 563 K. Further, x = 0.025 Al substitution in Bi2-xAlxS3 leads to a high power factor of 338 Wm−1K-2 and a low phonon thermal conductivity of 0.578 μWm−1K−1, leading to a maximum zT of 0.30 at 623 K.

A novel LaAl1-xNbxO3 NTC ceramic with excellent stability for high-temperature thermistor

A series of LaAl1-xNbxO3 (0 ≤ x ≤ 0.100) samples were synthesized via the solid phase method. Characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) confirmed the formation of a solid solution in LaAl1-xNbxO3 (0 ≤ x ≤ 0.100) materials without the emergence of additional phases following Nb doping. Transmission electron microscopy (TEM) revealed distinct lattice fringes with a d value of 0.274 nm, corresponding to the (110) plane of LaAlO3 (PDF #82–0478). The introduction of Nb dopant caused distortions in the cell parameters of LaAlO3 due to ionic radius size effects, changes in Nb valence, fluctuations in oxygen vacancy concentration and Coulomb forces. Specifically, the lattice exhibited a shrinkage for 0 ≤ x ≤ 0.025, expansion for 0.025 <x ≤ 0.075, and subsequent shrinkage for 0.075 <x ≤ 0.100. Resistance measurements indicated that LaAl1-xNbxO3 (0 ≤ x ≤ 0.100) materials exhibited favorable negative temperature coefficient (NTC) characteristics in the temperature range of 600 °C–1400 °C. Hall measurements revealed that the materials functioned as P-type semiconductors with hole carriers, and Nb doping enhanced carrier concentration. Aging tests demonstrated that the aging drift rate of LaAl0.9Nb0.1O3 could be as low as 0.906% after aging it at 1000 °C for 500 h, a crucial parameter for practical applications of LaAl1-xNbxO3 (0 ≤ x ≤ 0.100) materials in high-temperature NTC applications.

Spin chiral interactions modulated Seebeck coefficient and improved optical properties by Zn doping in CuCrO2 crystallites

Future electronics hold a special promise for flexible, optically translucent thermoelectric devices. Here, we demonstrate the better thermoelectric performance of p-type transparent CuCrO2 crystallites by the insertion of non-magnetic Zn2+ in magnetic Cr3+ site at room and high temperatures. Doping induced increase in charge carrier density generally leads to elevated carrier scattering, which in turn diminishes the voltage generated per unit tem-perature difference and causes a decrease in the Seebeck coefficient. Balancing the Seebeck coefficient and conductivity is a crucial challenge in the design of thermoelectric materials. By introducing non-magnetic doping, the anti-ferromagnetic order of Cr3+ ions is destabilized, resulting in a modification of the spin configuration. This alteration gives rise to spin chiral interactions, which, in turn, contribute to the generation of an exceptionally large Seebeck coefficient of 582 μV/K at 100 °C. The insertion also generates anisotropic microstrains in the structure and the structural changes were investigated by XRD analysis, FTIR, and Raman spectroscopy. Carrier concentration and carrier mobility were measured by Hall measurements techniques and has shown increasing and decreasing trend respectively with the increase of the doping percentage of Zn2+. Optical studies were done by UV–Vis analysis and found the maximum band gap of 3.04 eV for 0.5 wt% doped CuCrO2 and the absorption spectra revealed the defect induced in the structure comprehending the Raman analysis. The enhancement of carrier concentration and mobility led to increased conductivity of 2096 S/m and power factor of 411 μW/mK2 for the sample 0.3 wt% at 700 °C. The Seebeck coefficient of the sample dropped as the temperature rose, but it was maintained in the range of 440–580 μV/K, which is found as the primary characteristic of Zn doping. Thermal conductivity is found as decreased with doping and the highest ZT obtained is 0.199 for 0.3 wt% doped sample at 700 °C. The higher thermoelectric performance and optical transmission at visible wavelength can be put together in optoelectronic devices.

Magneto-Transport and Enhanced Spin-Polarized Photo Response in Solution-Processed Vertically Aligned Zn0.9Ni0.1O Nanowires

In this study, we grew pristine and Ni-doped vertically aligned zinc oxide nanowires (NWs) on a glass substrate. Both the doped and pristine NWs displayed dominant 002 peaks, confirming their vertical alignment. The Ni-doped NWs exhibited a leftward shift compared to the pristine NWs. TEM measurements confirmed the high crystallinity of individual NWs, with a d-spacing of ~0.267 nm along the c-axis. Ni-doped NWs had a higher density, indicating increased nucleation sites due to nickel doping. Doped NW films on glass showed enhanced absorbance in the visible region, suggesting the creation of sub-gap defect levels from nickel doping. Magnetization vs. magnetic field measurements revealed a small hysteresis loop, indicative of soft ferromagnetic behavior. Current transient plots demonstrated an increase in current with an applied magnetic field. Two-terminal devices exhibited a photo response that intensified with magnetic field application. This increase was attributed to parallel grain alignment, resulting in enhanced carrier concentration and photo response. In the dark, transport properties displayed negative magnetoresistance behavior. This magneto-transport effect and enhanced photo response (under an LED at ~395 nm) were attributed to giant magnetoresistance (GMR) in the aligned NWs. The observed behavior arose from reduced carrier scattering, improved transport properties, and parallel spin alignment in the magnetic field.

Thermoelectric properties of p-type Mg2Si0.3Sn0.7 doped with silver and gallium

Structure, composition, and transport properties of Mg2−xAgx(Si0.3Sn0.7)1−yGay (x = {0, 0.02}, y = {0, 0.02, 0.04, 0.06}) solid solutions produced by melting followed by spark plasma sintering are investigated. The preparation method is adjusted to control sample stoichiometry and phase composition. Doping with two types of dopants at different sites, while employing synthesis methods which generate a small amount of secondary phase, is an uncommon approach in this materials, expected to enhance their thermoelectric performance. An enhanced carrier concentration but diminished mobility is observed in the samples with higher amounts of dopant, which leads to the highest values of the power factor, for Mg1.98Ag0.02Si0.27Sn0.67Ga0.06 in a narrow temperature range (575–675 K) around the peak value, of 9.10−4 Wm−1 K−2 at 625 K. The two types of dopants have opposing effects on the thermal conductivity, with Ag promoting strong phonon scattering and decreasing its values while Ga increases them because of its enhanced carrier concentration. The rather high thermal conductivity values of the double doped compounds produce low values of the ZT without exceeding 0.29 at 627 K for Mg1.98Ag0.02Si0.3Sn0.7 sample.

Controllable 2H/3R phase transition and conduction behavior change in MoSe2:Nb substitution by high pressure synthesis for promising thermoelectric conversion

Transition metal dichalcogenides (TMDs) are uniquely multifunctional materials with optical, electronic, and catalytic properties. Despite the advantages of low cost, low toxicity, and high abundance, the thermoelectric transport properties of MoSe2 were not extensively investigated. Meanwhile, MoSe2 bulk material with 3R phase was rarely reported compared to 2H phase. In this work, controllable phase transition from 2H to 3 R for MoSe2 bulk polycrystalline material was achieved with various Nb contents by a simple and feasible high-pressure method. The preferred orientation resulted in anisotropy of both electrical and thermal transport. The samples converted from n type for pristine sample to p type conduction after Nb doping. Meanwhile, the conduction type gradually changed from semiconductor to degenerated semiconductor. The electrical properties were distinctly improved by Nb doping systematically from the reduced bandgap and the enhanced carrier concentration and mobility. The lattice thermal conductivity was reduced by point defects and grain/phase boundaries generating from Nb doping. Maximum zT of 0.17 at 873 K was obtained for Nb0.04Mo0.96Se2, which is among the highest values for Te-free Mo dichalcogenides. The strategy of chemical doping and high-pressure synthesis provides an alternative route to achieve MoSe2 bulk materials with a controllable 2H/3R phase ratio for potential applications, which can be extended to other TMDs.

Electronic Structure Manipulation of the Mott Insulator RuCl3 via Single-Crystal to Single-Crystal Topotactic Transformation.

The core task for Mott insulators includes how rigid distributions of electrons evolve and how these induce exotic physical phenomena. However, it is highly challenging to chemically dope Mott insulators to tune properties. Herein, we report how to tailor electronic structures of the honeycomb Mott insulator RuCl3 employing a facile and reversible single-crystal to single-crystal intercalation process. The resulting product (NH4 )0.5 RuCl3 ⋅1.5 H2 O forms a new hybrid superlattice of alternating RuCl3 monolayers with NH4 + and H2 O molecules. Its manipulated electronic structure markedly shrinks the Mott-Hubbard gap from 1.2 to 0.7 eV. Its electrical conductivity increases by more than 103 folds. This arises from concurrently enhanced carrier concentration and mobility in contrary to the general physics rule of their inverse proportionality. We show topotactic and topochemical intercalation chemistry to control Mott insulators, escalating the prospect of discovering exotic physical phenomena.

Electronic Structure Manipulation of the Mott Insulator RuCl3 via Single‐Crystal to Single‐Crystal Topotactic Transformation

AbstractThe core task for Mott insulators includes how rigid distributions of electrons evolve and how these induce exotic physical phenomena. However, it is highly challenging to chemically dope Mott insulators to tune properties. Herein, we report how to tailor electronic structures of the honeycomb Mott insulator RuCl3 employing a facile and reversible single‐crystal to single‐crystal intercalation process. The resulting product (NH4)0.5RuCl3⋅1.5 H2O forms a new hybrid superlattice of alternating RuCl3 monolayers with NH4+ and H2O molecules. Its manipulated electronic structure markedly shrinks the Mott–Hubbard gap from 1.2 to 0.7 eV. Its electrical conductivity increases by more than 103 folds. This arises from concurrently enhanced carrier concentration and mobility in contrary to the general physics rule of their inverse proportionality. We show topotactic and topochemical intercalation chemistry to control Mott insulators, escalating the prospect of discovering exotic physical phenomena.

Synergistic effect of polypyrrole modified WS2 nanosheets on visible light assisted catalysis for the removal of chromium (VI) and humic acid

In this work, a novel nanocomposite was synthesized by the surface modification of tungsten disulphide (WS2) with polypyrrole (PPy) for the photocatalytic removal of heavy metal ions (chromium hexavalent (Cr (VI)) and natural organic contaminant (humic acid (HA)). The morphological analysis of synthesized samples was carried out using Field Emission Scanning Electron Microscopy (FESEM) which shows that PPy nanoparticles (NPs) are randomly distributed on the surface of WS2 nanosheets (NSs). The interlayer spacing of fringe width of WS2 NSs calculated from High Resolution Transmission Electron Microscopy (HRTEM) studies comes out to be 0.65 nm also in coherence with XRD analysis. Elemental analysis of synthesized nanocomposite was confirmed by using X-Ray Photoelectron Spectroscopy (XPS). The synthesized WP nanocomposite shown enhanced efficiencies (ɳCr ∼98.75% and ɳHA ∼77.78%) as compared to negligible efficiency of pristine WS2 (∼15% and 16%) and PPy (∼49% and 40%) for the reduction of Cr (VI) and degradation of HA, respectively. The enhanced removal efficiency of nanocomposite was attributed to decrease in the bandgap (2.03 to 1.80 eV), enhanced carrier concentrations (4.0 × 1030 cm−3 to 3.2 × 1031 cm−3) and low recombination rate (1.85 to 7.40 ns) of WP nanocomposite on the incorporation of PPy in WS2 as evident from UV–Vis, Mott-Schottky technique (MSK) and Time-correlated single-photon counting (TCSPC) decay measurement, respectively. The enhancement in removal efficiency is also attributed to the high surface area (160.36 m2/g) of the nanocomposite as analyzed using Brunauer-Emmett-Teller (BET) technique. The photocatalytic reduction efficiency was also studied as a function of pH (4,7 and 9). The reduction pathways follow second-order rate kinetics with high value of correlation coefficient (R2 ∼ 0.99). The proposed photocatalytic reduction mechanism was supported by a trapping study which shows that the superoxide radicals (⋅O2−) were the primary species taking part in photocatalytic reaction. Reusability test and stability of materials demonstrates promising photocatalytic performance of the synthesized nanocomposite.

Geometric, electronic and transport properties of bulged graphene: A theoretical study.

Out-of-plane deformation in graphene is unavoidable during both synthesis and transfer procedures due to its special flexibility, which distorts the lattice and eventually imposes crucial effects on the physical features of graphene. Nowadays, however, little is known about this phenomenon, especially for zero-dimensional bulges formed in graphene. In this work, employing first-principles-based theoretical calculations, we systematically studied the bulge effect on the geometric, electronic, and transport properties of graphene. We demonstrate that the bulge formation can introduce mechanical strains (lower than 2%) to the graphene's lattice, which leads to a significant charge redistribution throughout the structure. More interestingly, a visible energy band splitting was observed with the occurrence of zero-dimensional bulges in graphene, which can be attributed to the interlayer coupling that stems from the bulged structure. In addition, it finds that the formed bulges in graphene increase the electron states near the Fermi level, which may account for the enhanced carrier concentration. However, the lowered carrier mobility and growing phonon scattering caused by the formed bulges diminish the transport of both electrons and heat in graphene. Finally, we indicate that bulges arising in graphene increase the possibility of intrinsic defect formation. Our work will evoke attention to the out-of-plane deformation in 2D materials and provide new light to tune their physical properties in the future.

Oxygen-Vacancy Abundant Nanoporous Ni/NiMnO3/MnO2@NiMn Electrodes with Ultrahigh Capacitance and Energy Density for Supercapacitors.

High-performance energy storage devices (HPEDs) play a critical role in the realization of clean energy and thus enable the overarching pursuit of nonpolluting, green technologies. Supercapacitors are one class of such lucrative HPEDs; however, a serious limiting factor of supercapacitor technology is its sub-par energy density. This report presents hitherto unchartered pathway of physical deformation, chemical dealloying, and microstructure engineering to produce ultrahigh-capacitance, energy-dense NiMn alloy electrodes. The activated electrode delivered an ultrahigh specific-capacitance of 2700 F/cm3 at 0.5 A/cm3. The symmetric device showcased an excellent energy density of 96.94 Wh/L and a remarkable cycle life of 95% retention after 10,000 cycles. Transmission electron microscopy and atom probe tomography studies revealed the evolution of a unique hierarchical microstructure comprising fine Ni/NiMnO3 nanoligaments within MnO2-rich nanoflakes. Theoretical analysis using density functional theory showed semimetallic nature of the nanoscaled oxygen-vacancy-rich NiMnO3 structure, highlighting enhanced carrier concentration and electronic conductivity of the active region. Furthermore, the geometrical model of NiMnO3 crystals revealed relatively large voids, likely providing channels for the ion intercalation/de-intercalation. The current processing approach is highly adaptable and can be applied to a wide range of material systems for designing highly efficient electrodes for energy-storage devices.

Intermediate electron trap levels generation and enhanced carrier concentration in ZnO by strontium and molybdenum co-doping: an effective approach for dye degradation

Intermediate electron trap levels generation and enhanced carrier concentration in ZnO by strontium and molybdenum co-doping: an effective approach for dye degradation

Enhancement of charge transfer rate at mixed morphology TiO2/graphene interface by Al3+

Applying conductive coatings on the surface of non-conductive materials can effectively reduce the hazards caused by static electricity during the production process. However, commercially available TiO2 conductive powder relies on rare minerals and produces waste acids and bases. Therefore, we prepared Al-doped TiO2/graphene composites, which combine the advantages of TiO2 homojunction, ion doping, heterojunction, and rod morphology with excellent electrical conductivity (0.161 Ω·cm). In particular, the doping of Al3+ doubles its conductivity. This is due to the introduction of Al3+, which generates oxygen vacancies and so increases the carrier concentration. Furthermore, the introduction of Al3+ generates new conductive pathways (Al–O–C) and increases the content of highly electrochemically active oxygen-containing functional groups, leading to a significant enhancement of carrier transfer efficiency. Accordingly, the enhanced carrier concentration and transfer efficiency enhance the conductive properties of T-G-Al and provide new ideas for the preparation of conductive coatings.

SWCNTs/Ag2Se film with superior bending resistance and enhanced thermoelectric performance via in situ compositing

High power factor contributes high power generation output while high bending resistance extends the service life in flexible thermoelectric device. Here, we report an in situ grown 10 mol% single-walled carbon nanotubes (SWCNTs) and Ag2+ySe (named as 10 mol% SWCNTs/Ag2+ySe) film, which shows a high power factor of 19.36 μWcm−1 K−2 at 300 K and excellent bending resistance. Such a high power factor is attributed to the enhanced carrier concentration and enlarged effective mass, induced by the additional interstitial Ag in the in situ grown Ag2Se on SWCNTs. Moreover, the 10 mol% SWCNTs/Ag2+ySe film can remain 95 % of the initial electrical conductivity after 1000 bending cycles at the radius of 5 mm, indicating an excellent bending resistance. In addition, this film was assembled into a flexible thermoelectric power generator, which can achieve an output power of 0.72 μW and an open-circuit voltage of 18.17 mV at a temperature difference of 30 K. This study indicates that in situ compositing Ag2Se on SWCNTs can realize the increased thermoelectric performance and bending resistance, which drives the application of Ag2Se-based flexible films.

Enhanced thermoelectric performance of n-type Bi2Te2.7Se0.3 via a simple liquid-assisted shear exfoliation

• By using a simple approach of liquid-assisted shear exfoliation (LASE) coupled with SPS, highly-oriented bulk ceramics of Bi 2 Te 2.7 Se 0.3 with effectively reduced grain size were obtained. • A peak ZT value of 0.83 at 448 K was obtained in-plane due to a synergy of enhanced power factor and suppressed lattice and bipolar thermal conductivities, which is 95% higher that of the pristine sample, demonstrating LASE as a useful assistant process for enhancing the performance of layered thermoelectric materials. A liquid-assisted shear exfoliation (LASE) as a new powder metallurgy method coupled with spark plasma sintering (SPS) was applied for n -type Bi 2 Te 2.7 Se 0.3 and the effects on microstructure and anisotropic transport properties were investigated. Results revealed an effective reduction of average grain size due to LASE and a high texturing in the bulks. Moreover, along the in-plane direction, electrical conductivity was increased noticeably due to an enhanced carrier concentration, leading to a significantly improved power factor of 25 μW cm –1 K –2 at 303 K. Meanwhile, the total thermal conductivity was reduced effectively owing to reduction both in lattice component due to enhanced phonon scattering with the grain size reduction, and in the bipolar component inhibited by the increased carrier concentration. Ultimately, a peak thermoelectric figure of merit (ZT) value of 0.83 was obtained at 448 K along the in-plane direction, increased by 95% compared with the pristine one. These results demonstrate the LASE process as a useful assistant method for enhancing the TE performance of layered materials.

Thermoelectric properties and transport mechanism of Cu0.5In0.5Cr2Se4 and its Zn-doped samples

The thermoelectric properties and transport mechanism of Cu0.5In0.5Cr2Se4 and its Zn-doped samples were studied. In the middle and low temperature range, the electrical resistivity of Cu0.5In0.5Cr2Se4 decreases and Seebeck coefficient increases with the increase of temperature, indicating the fixed range hopping behavior of Anderson's localization. Two abnormal declines emerge simultaneously in resistivity and Seebeck coefficient at high temperatures, indicating a band regulation by temperature. After slight Zn-doping, the carrier concentration decreases slightly and the carrier mobility increases obviously, realizing electron delocalization. Both of resistivity and Seebeck coefficient decrease with further increasing Zn doping content due to the enhanced carrier concentration, resulting in the improved power factor. The thermal conductivity is extremely low in the pristine Cu0.5In0.5Cr2Se4 and increases with increasing Zn-doping. Due to the significant enlargement of power factor and relatively weak increase of thermal conductivity, the ZT value is enhanced by Zn doping from 0.30 of the pristine sample to 0.40 for the sample with 3.5% Zn doping at 773 K. Moreover, a factor of about 60% improvement of the average ZT is reported on the Zn-doped Cu0.5In0.5Cr2Se4 sample, reaching 0.26 over the temperature range between 323 K and 773 K.