Se Te Research Articles

A significant enhancement in thermoelectric power factor of In2Te3 thin films by Se doping and Te composition tuning

Thermoelectric power factor of a material significantly relies on its electrical conductivity, thermal conductivity, and Seebeck coefficient. Herein, an attempt has been made to enhance the thermoelectric power factor of In2Te3 thin films by tuning their Te composition and via Se doping. The optimum Se-doping concentration and Te composition enhanced the power factor of pristine In2Te3 films by 14 and 7.4 times, respectively. The modified chemical composition, structural characteristics, and surface morphological features of In2Te3 films are observed to be pivotal in improving their thermoelectric power factor. Overall, this study offers a facile approach to control the thermoelectric power factor of In2Te3 thin films which is significant for their futuristic applications.

Epithermal Au–Ag–Se–Te Deposits of the Chukchi Peninsula (Arctic Zone of Russia): Metallogeny, Mineral Assemblages, and Fluid Regime

Abstract Numerous epithermal Au–Ag deposits and ore occurrences of the Chukchi Peninsula are localized in the Cretaceous Okhotsk–Chukotka (OCVB) continent-marginal and Late Jurassic–Early Cretaceous Oloi (OVB) island arc volcanic belts and in Early Cretaceous postcollisional volcanic troughs. Volcanotectonic depressions, calderas, and volcanic domes control the location of the deposits. The orebodies of the deposits are quartz–adularia veins, sometimes en-echelon ones forming extending vein zones, as well as isometric and linear stockworks. The auriferous veins of most deposits display complex breccia–crustification structures. The vein ores have rhythmically and colloform–banded structures, with a predominantly fine distribution of ore mineral grains, often with banded clusters of ore minerals (ginguro). Native gold is of low fineness; the dispersion of this index varies from low to high. Acanthite is widespread in the ores. Its highest contents are specific to deposits with the repeated redistribution of substance (Kupol, Corrida, and Valunistoe). Based on the results of mineralogical studies, most of the epithermal Au–Ag deposits of the Chukchi Peninsula can be assigned to the Se type. The ores of some deposits (Valunistoe, Dvoinoe, etc.) contain both Se and Te minerals. The telluride-richest sites of the Sentyabr’skoe and Televeem deposits are far from the main orebodies. Most of the Chukchi epithermal Au–Ag deposits have many common characteristics (low and moderate temperatures of fluids, low fluid salinity, domination of carbon dioxide over methane, etc.) typical of low-sulfidation deposits. The maximum temperatures and salinity are specific to fluids in the Central Chukchi sector of the OCVB and in the Baimka zone of the OVB, and the minimum ones are typical of fluids in the East Chukchi flank zone and inner zone of the OCVB. The average salinity of mineral-forming fluids in the inner zone of the OCVB is half as high as the salinity of fluids in the East Chukchi flank zone of this belt, although the sulfate content is higher. At the same time, the fluids in the inner zone of the OCVB are richer in carbon dioxide and bicarbonate ion than the fluids in the East Chukchi flank zone of this belt. The fluid inclusion data permit the Vesennee deposit (Baimka zone) to be regarded as an intermediate-sulfidation one and suggest the presence of epithermal high-sulfidation deposits in the inner zone of the OCVB.

A first principles investigation of ternary and quaternary II–VI zincblende semiconductor alloys

One of the most common ways of tuning the stability, electronic structure, and optical behavior of semiconductors is via composition engineering. By mixing multiple isovalent elements at any cation or anion site, new compositions may be generated with markedly different properties than end-point compositions, and not always lying within a predictable trend. In this work, we explore the trends in lattice constant, electronic band gap, formation and mixing energy, and optical absorption behavior in a series of II–VI zincblende semiconductors with Cd/Zn at the cation site and S/Se/Te at the anion site, using multiple levels of density functional theory approximations. We find that while the GGA-PBE functional reproduces all trends correctly, full geometry optimization with the HSE06 functional predicts band gaps with much higher experimental accuracy. We find that all mixed S–Se and mixed Cd–Zn compounds show linear trends in band gap, rising from Se to S and Cd to Zn, respectively, whereas all Se–Te mixed compounds exhibit band gap bowing. All mixing energy curves, calculated based on decomposition to end point compositions, show inverted bowing behavior but with small positive mixing energy values <50 meV per formula unit, indicating robust stability of all solid solutions. Formation energies, calculated based on decomposition to elemental species, always show linear trends and remain sufficiently negative for all binaries, ternaries and quaternaries, whereas lattice constants show expected linear trends. We further report trends in optical absorption spectra and relationships between PBE and HSE computed properties, which reveal equations that can be used to accurately predict higher fidelity data. This work lays out systematic trends in the stability and optoelectronic characteristics of Cd–Zn–S–Se–Te alloys and enables the selection of optimal compositions for desired applications.

Solution Processed Fabrication of Se–Te Alloy Thin Films for Application in PV Devices

Solution Processed Fabrication of Se–Te Alloy Thin Films for Application in PV Devices

Characterization of synthetic and natural gold chalcogenides by electron microprobe analysis, X‐ray powder diffraction, and Raman spectroscopic methods

AbstractElectron microprobe analysis (EMPA), X‐ray powder diffraction (XRD), and Raman spectroscopy (RS) were applied to characterize the synthetic gold chalcogenides of the Au–Te–Se–S system and natural analogs from the Gaching deposit (Central Kamchatka, Russia). The EPMA results showed that the synthetic chalcogenides have different Te/Se/S and Au/X (X = Te + Se + S) ratios: AuX2, Au3X10, and AuX. They are similar in composition to natural compounds — calaverite (AuTe2), maletoyvayamite (Au3Te6Se4), and unnamed minerals AuTe0.7Se0.3 and AuSe0.7S0.3. It was established that chalcogenides AuX, Au3X10, and AuX2 have a specific Raman spectra with characteristic peaks. The position of the peaks and the character of the spectra of the synthetic phases and their natural analogs from the Gaching deposit coincide within the limits of accuracy. Different ratios of chalcogenes Te/Se/S in compounds influence the Raman peak positions. The positions of the peaks for natural compounds AuX differ depending on the predominance of Te (AuTe0.7Se0.3) or Se (AuSe0.7S0.3). AuSe synthetic phases consist of a mixture of α‐ and β‐polymorphs. Raman spectroscopy can be used for the identification of natural gold chalcogenides worldwide, which are difficult to diagnose by other methods due to the microscopic grain sizes and close intergrowths with other ore minerals. The similarity of the Raman spectra upon changing the concentrations of Se and S suggests identical structures and possible isomorphism in the composition range of AuTe0.7Se0.3– AuTe0.7Se0.2S0.1, AuTe1.9Se0.1– AuTe1.8Se0.1S0.1, and Au3Te6Se4– Au3Te6S3Se.

Application of lithogeochemical and pyrite trace element data for the determination of vectors to ore in the Raja Au–Co prospect, northern Finland

Abstract. Discovering ore deposits is becoming increasingly difficult, and this is particularly true in areas of glaciated terrains. As a potential exploration tool for such terrains, we test the vectoring capacities of trace element and sulfur isotope characteristics of pyrite, combined with quantitative statistical methods of whole-rock geochemical datasets. Our target is the Rajapalot gold–cobalt project in northern Finland, where metamorphosed Paleoproterozoic volcanic and sedimentary rocks of the Peräpohja belt host recently discovered gold prospects, which also have significant cobalt enrichment. The focus is particularly put on a single gold–cobalt prospect, known as Raja, an excellent example of this unusual cobalt-enriched gold deposit, common in the metamorphosed terranes of northern Finland. The major lithologies at Rajapalot comprise amphibolite facies metamorphosed and polydeformed calcsilicate rocks that alternate with albitic units, mafic volcanic rocks, mica schist and quartzite. Mineralization at Rajapalot prospects is characterized by an older Co-mineralizing event and a younger high-grade Au mineralization with re-mobilization and re-deposition of Co. Detailed in situ laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a powerful technique that produces robust trace element and sulfur isotope databases from paragenetically and texturally well-characterized pyrite from the Raja prospect. The results are treated with appropriate log-ratio transformations and used for multivariate statistical data analysis, such as the computation of principal components. Application of these methods revealed that elements such as Co, Ni, Cu, Au, As, Ag, Mo, Bi, Te, Se, Sn, U, Tl and W have high vectoring capacities to discriminate between Co-only and Au–Co zones, as well as between mineralization stages. The systematic pyrite study suggests that homogenous sulfur isotopic characteristics (+1.3 ‰ to +5.9 ‰) and positive loadings of Co, Se, As, Te, Bi and Au onto PC1 are reflective of an early stage of Co mineralization, while the opposing negative loadings of Mo, Ni, W, Tl, Cu and Ag along PC1 are associated with pyrites from the Au-mineralizing event. The sulfur isotopic signature of the latter pyrite type is between −1.2 ‰ and +7.4 ‰. Subtle patterns recognized from the whole-rock geochemistry favor an As–Au–Se–Te–W–U signature along the positive axis of PC1 for the localization of high-grade Au–Co zones, whereas the element group Ni, Cu, Co, Te, Se and As, which has negative loadings onto PC2, will predict Co-only zones. This study shows the efficiency of trace element geochemistry in mineral exploration targeting, which has the capacity to define future targets by characterizing the metallogenic potential of a host rock, as well as distinguishing various stages of mineralization.

A DFT study of Se n Te n clusters.

First principles calculations have been performed to study the characteristic properties of SenTen (n = 5–10) clusters. The present study reveals that the properties of these small clusters are consistent with the properties of Se–Te glassy systems. Several hundred equilibrium structures obtained from a genetic algorithm based USPEX code are relaxed to their minimum energy using the VASP code. Most of the lowest energy buckled ring-like structures are formed from Se–Te heteropolar bonds. Detailed structural analysis and distance energy plots unveil that many equilibrium structures are close in energy to their global minimum. The computed Raman and IR spectra show the dominance of Se–Te heteropolar bonds, consistent with earlier simulation and experimental findings in Se1−xTex glass materials. Low frequency vibrational modes observed in small clusters are characteristic features of amorphous materials. Non-bonding orbitals (lone pair) are observed in the HOMO, whereas the LUMO is formed from purely antibonding orbitals. The dielectric functions corroborate the bonding mechanism and slightly polar nature of SenTen clusters. The energy loss and absorption coefficient indicate the presence of π–plasmons in the UV-visible region. Furthermore, it is ascertained that the use of a hybrid functional (B3LYP) does not affect the properties of small clusters appreciably, except causing a blue shift in the optical spectra. Hence, we find that the small clusters have bearing on the formation of glassy Se–Te systems.

Voltage Loss Comparison in CdSe/CdTe Solar Cells and Polycrystalline CdSeTe Heterostructures

Cd(Se)Te solar cells have considerable headroom to increase voltage. Voltage losses occur due to incomplete absorption above bandgap <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E_g</i> and band tail absorption below <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E_g</i> ; such losses are quantified using radiative voltage. The largest voltage losses are attributed to nonradiative recombination, which is quantified via carrier lifetime and radiative efficiency. We compare radiative voltage, radiative efficiency, and carrier lifetime for Cu-doped CdSe/CdTe solar cells and for undoped polycrystalline CdSeTe heterostructures passivated with Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> . Using external quantum efficiency spectrum and a CdSeTe absorption spectrum obtained from absolute photoluminescence (PL), we show that the radiative voltage is greater than 1.1 V. Time-resolved PL experiments and modeling show that a major part of voltage losses can be attributed to recombination in the absorber bulk. The front interface recombination makes a larger impact within the first few nanoseconds after pulsed excitation, and the comparison of time-gated and time-integrated PL can be used to assess relative contributions of front interface and bulk recombination rates.

Extraction of thermal and optical parameters for As–Se–Te thin films according to phase-change pathways

The technique of thermal evaporation was used to synthesize the As50Se50-xTex (x = 0, 25, and 50 at.%) thin films (∼500 nm). The scenarios of this research were focused on the phase change pathways of the fresh and annealed (at Tc) thin films. By measuring the surface resistance of the studied thin films in the thermal range between 300 and 600 K, the path of phase transitions from the amorphous to the crystalline state was determined. The average activation energy of phase transitions was computed for the entire system. The phase-transition temperature has been determined utilizing the first derivative of the sheet resistance as a function of temperature (Rs–T). The optical bandgap of the fresh and annealed (at Tc) thin films was determined utilizing Kubelka–Munk (K-M) function that was extracted after measuring the diffuse reflectivity spectra in the range of (300–2500 nm). The two molar optical constants (n, k), the molar dispersion and dielectric parameters have been computed. Values of effective plasmon energy (Ψ), Molar volume Vm, the effective number of electrons neff, the electron density parameter rs, the homopolar gap (E‾h), the heteropolar gap (C), the average gap (E‾g), the theoretical static dielectric constant (ε0th) and Phillips ionicity of the glasses under study were calculated according to Penn model. All computed parameters in this work were given to the phase change paths in the studied system to consider the possibility of using the chalcogenide system in the phase-change memory (PCM) applications.

Building ultra-stable K–Te battery by molecular regulation

Tellurium (Te) is an ideal electrode for potassium ion batteries (PIBs) owing to its excellent electronic conductivity and high volumetric capacity. However, the Te electrode is prone to capacity fading as the shuttle effect. To address this challenge, we propose molecular regulated Se–Te solid solutions on N-doped porous carbon as the PIBs electrode. After optimizing the Se content in Se–Te solid solutions, the resultant SeTe6.8 on N-doped porous carbon (SeTe6.8@C) delivered a capacity of over 400 mAh g−1 with a flat plateau of 1.0 V at 500 mA g−1. It also achieved a superiorly long cycle life, running for more than 1600 cycles (over 7 months with 0.015% degeneration per cycle) at 100 mA g−1 and excellent rate performance (179.9 mAh g−1 at 10000 mA g−1). This remarkable electrochemical energy storage of the Te electorde likely arises from suppression of the shuttle effect after doping the Te with strongly electronegative Se atoms (forming K5Te3 which is not easily soluble in electrolyte). This study presents a fresh approach for designing and developing ultra-stable Te-based electrodes for PIBs and beyond.

High-Performance Humidity Sensing of Arsenic Based Chalcogenide Thin Films at Different Frequencies

Present paper consists of the study of arsenic-based chalcogenide thin film for sensing elements for humidity sensors. The chemical composition of the prepared sensing element makes it more sensitive towards water molecule absorption and hence affects sensitivity. The bulk samples of Ge–Se–Te–As composition were prepared using the conventional melt-quench technique and the thin films were obtained using the thermal evaporation method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the structural characteristics of the prepared sensing element. Tauc’s plot, using UV-Vis spectrophotometer data, was used to determine the optical bandgap of the sensing materials. The relative humidity (RH) variation of the prepared sensing element was recorded in the range of 10%–90%. The sensitivity of the prepared sensing membrane was obtained as 8.54 MΩ/%RH, 9.724 MΩ/%RH, 10.257 MΩ/%RH for x = 10, 20, 30 respectively. The repeatability of the prepared samples was also reported to increase with Arsenic concentration.

Control of Cu-doping behavior in n-type Cu0.01Bi1.99Te2.7Se0.3 polycrystalline bulk via fabrication technique change

Bi–Te-based alloys are potential candidates for use in thermoelectric (TE) modules for low-mid-temperature energy harvesting. However, n -type Bi–Te–Se alloys are inferior to their p -type counterparts in terms of TE performance. It has been found that doping Cu atoms into n -type Bi–Te–Se alloys is effective in improving the TE properties; however, different studies have reported contrasting roles of Cu dopants in the transport properties of Bi–Te–Se alloys. This is attributed to the complex doping behaviors of Cu atoms. In this study, it is demonstrated that employing an appropriate fabrication technique can enable more Cu dopants to be directed to specific atomic sites than others. As part of the study, two n -type polycrystalline Cu 0.01 Bi 1.99 Te 2.7 Se 0.3 bulk samples are respectively fabricated via melt-spinning followed by spark plasma sintering, and via ball-milling followed by spark plasma sintering. The majority of Cu dopants in the melt-spun sample are suspected to exist in between Te 1 –Te 1 atomic layers (van der Waals gap), given the elongated c -axis, increased Hall carrier concentration, and improved non-degenerate mobility (intercalated Cu generates one electron and acts as an electric connector). Resultantly, a ~30% enhancement in the TE figure-of-merit (~0.92 at 360–400 K) is achieved in the melt-spun sample, relative to the ball-milled sample, wherein Cu atoms substitute Bi atoms.

Density of states, DC conductivity and physical properties of Ag2S-Ge–Te–Se chalcogenide glassy system

Density of states, DC conductivity and physical properties of Ag2S-Ge–Te–Se chalcogenide glassy system

Characterizing the Back-Contact Interface of Poly-Crystalline Cd(Se)Te Devices with XEDS, EELS, and HRSTEM

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Selenium and tellurium in Reykjanes Ridge and Icelandic basalts: Evidence for degassing-induced Se isotope fractionation

Selenium behaves as a chalcophile and moderately volatile element during planetary accretion and magmatic processes on Earth. Together with the geochemically similar S and Te, Se is more volatile than most other moderately volatile elements and thus potentially becomes a new tracer to constrain the mechanism of volatile depletion in the Earth’s mantle and other planetary bodies. As previously observed for several volatile elements, stable isotopes of Se are expected to fractionate upon eruptive outgassing of magmas. To understand the degassing behavior of Se and associated isotope fractionation, we report on Se and Te contents and Se isotope compositions (δ82Se) of submarine glasses across a range of distant ridge depth intervals along the Reykjanes Ridge and subglacial/subaerial basalts on Iceland (51–65°N; N = 22). Selenium (150–399 ng/g) and Te (2.61–14.5 ng/g) contents of the submarine glasses display progressive enrichment along the Reykjanes Ridge towards Iceland. This can be explained either by enhanced mantle melting towards Iceland or by enrichment of Se–Te contents in the mantle source due to the Icelandic plume–Reykjanes Ridge interaction. Both scenarios are equally plausible. The δ82Se values of submarine Reykjanes Ridge glasses range between −0.20 ± 0.08‰ and −0.08 ± 0.08‰ (on average −0.15 ± 0.07‰; 2SD, N = 15), which are unaffected by the Icelandic plume contribution and remain strictly within the previously reported average for depleted MORBs. These new data combined with literature δ82Se for depleted MORBs define a highly homogeneous depleted mantle composition δ82Se = −0.15 ± 0.11‰ (2SD, N = 44). On the other hand, we observed degassing of Se and Te to a variable extent (~40–95%) in submarine Reykjanes glasses at depths shallower than ~250 m and in subaerial/subglacial basalts on Iceland. Degassing-induced Se isotope fractionation shifted δ82Se of subaerial lavas towards heavier values (by up to ~0.44‰) well outside the range of submarine MORBs. However, when Se outgassing is associated with subglacial eruption, the outer glass rim of basalt preserves the primary/undegassed Se isotopic signature; whereas the pillow interior experiencing further Se loss (~50%) is enriched in heavier isotopes (−0.01 ± 0.12‰) relative to the outer glass rim (−0.22 ± 0.08‰). These observations are complemented by measurements of BHVO-2G from high-temperature heating experiments of the natural Hawaiian basalt BHVO-2, which show evaporation of 40% Se and 85% Te and resulting shift in δ82Se by ~+0.74‰. Degassing-induced Se isotope fractionation during volcanic eruption may be well explained by a simple Rayleigh distillation model with an empirical fractionation factor α of ~0.9998 (between volcanic gas and silicate melt). The results presented here show that Se isotope and Se–Te systematics can potentially contribute further constraints on degassing of chalcophile and volatile elements during terrestrial volcanism and large-scale planetary processes.

Optical and mechanical properties of Ag doped thermally evaporated SeTe thin films for optoelectronic applications

Se–Te materials have shown promise in optoelectronic applications. A combination of enhanced optical and mechanical properties represents a good candidate for optical limiting devices. Here, we report the influence of Ag additive on the optical and mechanical properties of (Se70Te30)100−xAgx(0.0≤x≤8.0at.%) chalcogenide thin films. The reflectance spectra of amorphous thin films have been analyzed in the spectral range 0.3 μm–2.5 μm. The optical parameters are obtained using reflectance spectra of the thin films. The refractive index increases with the addition of Ag, while the optical band gap decreases from 1.40 eV to 1.11 eV. The reduction in the optical band gap is correlated with the raise in the concentration of defect states and the disorder. The nonlinear refractive index and nonlinear susceptibility have been evaluated and found to show an augmented response with Ag content. The value of (χ(3)) increases from 3.44 × 10−11 esu to 7.66 × 10−11 esu and n2 from 3.98 × 10−10esu to 8.08 × 10−10esu. The mechanical properties have also been analyzed theoretically and ultrasonically with Ag incorporation to SeTe thin films.

Development of a spiral spin- and gradient-echo (spiral-SAGE) approach for improved multi-parametric dynamic contrast neuroimaging.

The purpose of this study was to develop a spiral-based combined spin- and gradient-echo (spiral-SAGE) method for simultaneous dynamic contrast-enhanced (DCE-MRI) and dynamic susceptibility contrast MRI (DSC-MRI). Using this sequence, we obtained gradient-echo TEs of 1.69 and 26 ms, a SE TE of 87.72 ms, with a TR of 1663 ms. Using an iterative SENSE reconstruction followed by deblurring, spiral-induced image artifacts were minimized. Healthy volunteer images are shown to demonstrate image quality using the optimized reconstruction, as well as for comparison with EPI-based SAGE. A bioreactor phantom was used to compare dynamic-contrast time courses with both spiral-SAGE and EPI-SAGE. A proof-of-concept cohort of patients with brain tumors shows the range of hemodynamic maps available using spiral-SAGE. Comparison of spiral-SAGE images with conventional EPI-SAGE images illustrates substantial reductions of image distortion and artifactual image intensity variations. Bioreactor phantom data show similar dynamic contrast time courses between standard EPI-SAGE and spiral-SAGE for the second and third echoes, whereas first-echo data show improvements in quantifying T1 changes with shorter echo times. In a cohort of patients with brain tumors, spiral-SAGE-based perfusion and permeability maps are shown with comparison with the standard single-echo EPI perfusion map. Spiral-SAGE provides a substantial improvement for the assessment of perfusion and permeability by mitigating artifacts typically encountered with EPI and by providing a shorter echo time for improved characterization of permeability. Spiral-SAGE enables quantification of perfusion, permeability, and vessel architectural parameters, as demonstrated in brain tumors.

Phase diagram of Pb–Se–Te system I: Experimental study

Pb–Se–Te ternary system is of significant importance for thermoelectric applications. However, no systematic study of its phase diagram has been carried until now. Samples of Pb–Se–Te ternary alloys were prepared, their phase equilibrium phases were determined, and the Pb–Se–Te isothermal sections at 350 °C and 500 °C were proposed based on the experimental results. No ternary compounds were found. There is one three phase field, Pb(Se,Te)+liquid(Se,Te)+(Se,Te) at 350 °C and no three phase field at 500 °C. PbSe and PbTe form a continuous solid solution at both temperatures.

The study of the Pb–Se–Te phase diagram: Part 2 – The thermodynamic assessment of the Se–Te and Pb–Se–Te systems

Pb–Se–Te ternary system is of significant importance for thermoelectric applications. In spite of this, no systematic experimental or theoretical study of its phase diagram has been carried out up to now. The CALPHAD type theoretical assessment was done in the scope of this work for the Se–Te and Pb–Se–Te systems based on our own experimental work and the experimental results from literature. It was found out that the reassessment of the existing Se–Te phase diagram assessments is necessary because of some discrepancies between the experimental results and calculations for this system. This new dataset was consequently used for the new assessment of the Pb–Se–Te system and very good agreement was reached with existing experimental data.

Modification of the Hybridization Gap by Twisted Stacking of Quintuple Layers in a Three-Dimensional Topological Insulator Thin FilmSupported by the National Natural Science Foundation of China (Grant Nos. 61804056 and 92065102).

Twisting the stacking of layered materials leads to rich new physics. A three-dimensional topological insulator film hosts two-dimensional gapless Dirac electrons on top and bottom surfaces, which, when the film is below some critical thickness, will hybridize and open a gap in the surface state structure. The hybridization gap can be tuned by various parameters such as film thickness and inversion symmetry, according to the literature. The three-dimensional strong topological insulator Bi(Sb)Se(Te) family has layered structures composed of quintuple layers (QLs) stacked together by van der Waals interaction. Here we successfully grow twistedly stacked Sb2Te3 QLs and investigate the effect of twist angels on the hybridization gaps below the thickness limit. It is found that the hybridization gap can be tuned for films of three QLs, which may lead to quantum spin Hall states. Signatures of gap-closing are found in 3-QL films. The successful in situ application of this approach opens a new route to search for exotic physics in topological insulators.