Trap Levels Research Articles

Carrier conduction mechanisms in MIS capacitors with ultra-thin Al2O3 at cryogenic temperatures

In this work, a study comprising the electrical characterization and analysis of the electrical response of metal–insulator–semiconductor Al/Al2O3/Si capacitors in a temperature range from ambient temperature down to 3.6 K is presented. An ultra-thin 6 nm Al2O3 film, deposited by atomic layer deposition, was used as an insulating layer. Current–voltage and electrical stress measurements were performed on the capacitors in the specified temperature range, and the experimental data obtained were analyzed using current transport equations to model the conduction mechanisms that allow charge transport through the Al2O3. Energetic parameters associated with trap levels within the Al2O3 bandgap corresponding to the Poole–Frenkel emission and trap-assisted tunneling mechanisms were obtained, and their temperature dependances were studied and associated with the presence of physical material defects. The analysis of the modeling results points to trap-assisted tunneling as the dominant mechanism at low temperatures for intermediate electric field values. Additional phenomena that limit charge transport were also observed, such as charge trapping in the bulk of the Al2O3 upon the application of electrical stress at ambient temperature and silicon freeze out at cryogenic temperatures. Our findings constitute an effort at understanding the physical phenomena that govern the electrical behavior of thin-film Al2O3-based capacitors, especially at cryogenic temperatures, given that these materials and devices are of considerable importance for applications in CMOS-based cryoelectronics and quantum technologies, among others.

MEDAG expression in vitro and paeoniflorin alleviates bone loss by regulating the MEDAG/AMPK/PPARγ signaling pathway in vivo

ObjectivesOsteoporosis (OP) is characterized by reduced bone mass and impaired bone microstructure. Paeoniflorin (PF) is isolated from peony root with anti-inflammatory, immunomodulatory, and bone-protective effects. Up to now, the mechanism of anti-OP in PF has not been completely clarified. MethodsThe expression of MEDAG in osteoclasts, osteoblasts and adipocytes was detected by RT-qPCR. The OVX mouse model was constructed, and oral administration of PF was performed for 15 weeks. Bone microstructure was detected by H&E staining and a micro-CT system, and expression of signaling proteins examined by Western blot and immunohistochemical staining. ELISA and biochemical kits were used to quantify serum metabolite levels. Key findingsMEDAG were upregulated in osteoclasts and adipocytes, and downregulated in osteoblasts. PF administration effectively alleviated OVX-induced bone loss, and histological changes in femur tissues. Moreover, PF significantly reduced serum TRAP, CTX-1, P1NP, BALP, and LDL-C levels and increased HDL-C. In addition, PF inhibited the expression of MEDAG, cathepsin K, NFATc1, PPARγ, and C/EBPα and increased p-AMPKα, OPG and Runx2. ConclusionsMEDAG is a potential target for bone diseases, and PF might attenuate OVX-induced osteoporosis via MEDAG/AMPK/PPARγ signaling pathway.

Improving insulation properties of epoxy filled with surface fluorinated polystyrene nanospheres

<sec>Epoxy resin nanocomposites are widely used in the field of electrical insulation packaging. It is of great significance to regulate the dielectric and insulation properties of composite materials by introducing nano-filler to meet special application requirements. This work proposes a chemical copolymerization method, fluorinated polystyrene nanospheres are synthesized through an addition reaction as filler, and finally the epoxy nanocomposites are prepared. The polystyrene nanospheres have a uniform size and good compatibility with the epoxy resin. The introducing of nanospheres reduces the dielectric constant of the epoxy resin composite material and increases the breakdown strength simultaneously. Although the dielectric loss increases, the composites’ imaginary part remains below 0.04 within 1 MHz frequency. In particular, the fluorinated polystyrene/epoxy composite with a mass fraction of 2% exhibits a decrease in dielectric constant and DC conductivity, while the AC breakdown strength and DC breakdown strength increase by 12.6% and 6%, respectively.</sec><sec>The results of the pulse electro-acoustic method indicate that the charge injection of the epoxy resin filled with non-fluorinated polystyrene nanospheres is evident, while the introduction of fluorinated nanospheres significantly reduces the charge injection level. Calculations based on the depolarization process reveal that the introduction of fillers leads to an increase in trap density and depth of energy levels in the composites. Notably, the epoxy resin filled with fluorinated fillers has the deepest trap levels, providing an explanation for the improved insulation breakdown performance. The research can provide guidance for regulating dielectric properties of epoxy composites and material synthesis for the application of electrical insulation packaging <b>.</b> </sec>

Silicon ultrafast recovery diode with leakage current reduced via the combined lifetime process of gold diffusion and electron-beam irradiation

We investigated the reduction in the reverse-biased leakage current of Si ultrafast recovery diodes via a combined lifetime process involving Au diffusion and bulk electron-beam irradiation (EI). The leakage current of the combined-processed diode was significantly reduced to less than one-third of that of the diode processed solely with Au diffusion, maintaining a similar switching time of 32 ns. This reduction was not achievable with the sole use of EI. Deep-level transient spectroscopy revealed that the reduction in the leakage current was due to the coexistence of the deep trap level of Au (E c-0.51 eV) and the shallow trap level of the defects (E c-0.39 eV) generated via EI as lifetime killers. By combining the deep and shallow trap levels, the lifetime of the carriers generated in the depletion layer of the reverse-biased p-n junction becomes long and consequently, the leakage current is reduced. By maintaining the trap density ratio of defects to diffused Au above 0.28, the leakage current was reduced to less than one-third of that in the solely Au-diffused diode, while maintaining a similar switching time.

Analysis and modeling of reverse-biased gate leakage current in AlGaN/GaN high electron mobility transistors

We have analyzed and modeled the reverse-biased gate leakage current in a Schottky-gate AlGaN/GaN high electron mobility transistor. While the Poole–Frenkel emission current along conductive threading dislocations dominates at low negative gate bias, the trap-assisted tunneling of thermally energized electrons and the thermal emission of electrons from threading dislocations aided by dislocation-related states at multiple energy levels within the AlGaN bandgap are dominant at moderate to large reverse bias. Additionally, deep trap levels of high density localized near the gate/AlGaN interface cause significant leakage at 473 K at low to moderate reverse bias, which could be specific to the device we have analyzed. We extracted about 1012 cm−2 traps near the AlGaN/GaN interface from the difference of the barrier layer electric field profile obtained from the experimental high-frequency capacitance–gate voltage and the one needed for final matching. The thermionic- and the thermionic field-emission currents are considerably low; the latter, however, dominates in the defect-free case. Finally, the simulation framework we developed here helped us identify various conduction mechanisms contributing to the reverse-biased gate leakage and the density and electronic structure of the responsible defects.

Radiation-induced thermoluminescence in Ca5(PO4)3OH powder from eggshell: Trapping parameter assessment

This study examines the thermoluminescence (TL) properties exhibited by hydroxyapatite (HAp) samples. The HAp samples were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. XRD results confirm that Hap corresponds to a hexagonal structure with a space group of P63/m. The study emphasizes the critical role of appropriate band-pass filters in TL measurements and explores the dose-dependent behavior of TL glow peaks. Examining the impact of varying heating rates (HR) on TL peak intensities revealed a positive correlation between HR and TL maximum peak temperatures, accompanied by a decrease in TL intensities. Notably, no thermal quenching effect was observed in HAp samples. The activation energy values were 0.51, 1.12, and 1.57 eV for Hoogenstraaten's method and 0.55, 1.19, and 1.65 eV for the Booth-Bohun-Porfianovitch method, demonstrating their consistency and robustness. Additionally, Tm-Tstop analysis was employed to identify distinct trap levels and calculate their respective activation energies. This study establishes a solid foundation for characterizing TL properties in HAp samples, shedding light on their potential applications in various fields. The findings provide valuable insights for the design and development of efficient catalysts for diverse applications.

Defects of perovskite semiconductor CsPbBr3 investigated via photoluminescence and thermally stimulated current spectroscopies

Halide perovskites are essential materials for hard radiation detectors at ambient temperature. To improve detector performance, charge transport must be investigated and optimized. Using photoluminescence (PL) and thermally stimulated current (TSC) spectroscopies, we investigate photogenerated charge carriers in Bridgman-grown CsPbBr3 single crystals to understand the nature of charge transport. PL spectroscopy of these halide perovskites revealed the presence of strong emission bands at the band edge, which were attributed to free or bound excitons. It is shown that a wide broadening of the excitonic linewidth in these halide perovskites arises from strong exciton–phonon coupling, which is substantially dominated by longitudinal optical phonons via Fröhlich interaction. An additional contribution due to the presence of ionized impurities was also observed. Crystals with a detectable sensitivity to high-energy gamma radiation are characterized by a higher intensity and a narrower linewidth of the principal PL peak at 2.326 eV. Defect states beyond 2.214 eV have a negative impact on detector sensitivity to high-energy gamma radiation. TSC spectroscopy reveals an array of trap levels spanning 0.15–0.70 eV, attributed to intrinsic point defects and multiple extrinsic defects involving dopants or impurities. Defects identified included Cs and Br vacancies, as well as Pb interstitials with concentrations in the 1011–1016 cm−3 range. Understanding how the synthesis process impacts the types and concentrations of the defects present is currently under investigation. Elimination or suppression of the defect/trap states should result in halide perovskite materials with longer carrier diffusion lengths and improved detector characteristics.

Hole diffusion effect on the minority trap detection and non-ideal behavior of NiO/β-Ga2O3 heterojunction

A NiO/β-Ga2O3 heterojunction was fabricated by sputtering a highly p-doped NiO layer onto β-Ga2O3. This heterojunction showed a low leakage current and a high turn-on voltage (Von) compared to a Ni/β-Ga2O3 Schottky barrier diode. The extracted Von from the NiO/β-Ga2O3 heterojunction's forward current–voltage characteristics was ∼1.64 V, which was lower than the extracted built-in potential voltage (Vbi) obtained from the capacitance–voltage curve. To explain this difference, deep level transient spectroscopy and Laplace-deep level transient spectroscopy were employed to study majority and minority traps in β-Ga2O3 films. A minority trap was detected near the surface of β-Ga2O3 under a reverse bias of −1 V but was not observed at −4 V, indicating its dependence on hole injection density. Using Silvaco TCAD, the hole diffusion length from P+-NiO to β-Ga2O3 was determined to be 0.15 μm in equilibrium, which is increased with increasing forward voltage. This finding explained why the trap level was not detected at a large reverse bias. Moreover, hole diffusion from NiO into β-Ga2O3 significantly affected the β-Ga2O3 surface band bending and impacted transport mechanisms. It was noted that the energy difference between the conduction band minimum (CBM) of β-Ga2O3 and the valence band maximum (VBM) of NiO was reduced to 1.60 eV, which closely matched the extracted Von value. This supported the dominance of direct band-to-band tunneling of electrons from the CBM of β-Ga2O3 to the VBM of NiO under forward bias voltage.

Silicon–van der Waals heterointegration for CMOS-compatible logic-in-memory design

Silicon CMOS-based computing-in-memory encounters design and power challenges, especially in logic-in-memory scenarios requiring nonvolatility and reconfigurability. Here, we report a universal design for nonvolatile reconfigurable devices featuring a 2D/3D heterointegrated configuration. By leveraging the photo-controlled charge trapping/detrapping process and the partially top-gated energy band landscape, the van der Waals heterostacking achieves polarity storage and logic reconfigurable characteristics, respectively. Precise polarity tunability, logic nonvolatility, robustness against high temperature (at 85°C), and near-ideal subthreshold swing (80 mV dec −1 ) can be done. A comprehensive investigation of dynamic charge fluctuations provides a holistic understanding of the origins of nonvolatile reconfigurability (a trap level of 10 13 cm −2 eV −1 ). Furthermore, we cascade such nonvolatile reconfigurable units into a monolithic circuit layer to demonstrate logic-in-memory computing possibilities, such as high-gain (65 at V dd = 0.5 V) logic gates. This work provides an innovative 3D heterointegration prototype for future computing-in-memory hardware.

Ni Single-Atoms Based Memristors with Ultrafast Speed and Ultralong Data Retention.

Memristor with low-power, high density, and scalability fulfills the requirements of the applications of the new computing system beyond Moore's law. However, there are still nonideal device characteristics observed in the memristor to be solved. The important observation is that retention and speed are correlated parameters of memristor with trade off against each other. The delicately modulating distribution and trapping level of defects in electron migration-based memristor is expected to provide a compromise method to address the contradictory issue of improving both switching speed and retention capability. Here, high-performance memristor based on the structure of ITO/Ni single-atoms (NiSAs/N-C)/Polyvinyl pyrrolidone (PVP)/Au is reported. By utilizing well-distributed trapping sites , small tunneling barriers/distance and high charging energy, the memristor with an ultrafast switching speed of 100ns, ultralong retention capability of 106 s, a low set voltage (Vset ) of ≈0.7V, a substantial ON/OFF ration of 103 , and low spatial variation in cycle-to-cycle (500 cycles) and device-to-device characteristics (128 devices) is demonstrated. On the premise of preserving the strengths of a fast switching speed, this memristor exhibits ultralong retention capability comparable to the commercialized flash memory. Finally, a memristor ratioed logic-based combinational memristor array to realize the one-bit full adder is further implemented.

Thermoluminescence Studies of Proton-Irradiated Cr-, Mg-Codoped β-Ga2O3.

Chromium-doped Ga2O3, with intense Cr3+-related red-infrared light emission, is a promising semiconductor material for optical sensors. This work constitutes a comprehensive study of the thermoluminescence properties of Cr-, Mg-codoped β-Ga2O3 single crystals, both prior to and after proton irradiation. The thermoluminescence investigation includes a thorough analysis of measurements with different β- irradiation doses used to populate the trap levels, with preheating steps to disentangle overlapping peaks (TM-TSTOP and initial rise methods) and finally by computationally fitting to a theoretical expression. At least three traps with activation energies of 0.84, 1.0, and 1.1 eV were detected. By comparison with literature reports, they can be assigned to different defect complexes involving oxygen vacancies and/or common contaminants/dopants. Interestingly, the thermoluminescence signal is enhanced by the proton irradiation while the type of traps is maintained. Finally, the pristine glow curve was recovered on the irradiated samples after an annealing step at 923 K for 10 s. These results contribute to a better understanding of the defect levels in Cr-, Mg-codoped β-Ga2O3 and show that electrons released from these traps lead to Cr3+-related light emission that can be exploited in dosimetry applications.

Thermal Stability of Schottky Contacts and Rearrangement of Defects in β‐Ga2O3 Crystals

AbstractThe thermal stability of different Schottky contacts (Au, Pt, and Ni) on (100) β‐Ga2O3 single crystals grown by the Czochralski method is investigated. Besides the examination of the Schottky barrier parameters, contact‐dependent defect levels are investigated by deep‐level transient spectroscopy (DLTS) in a 100–650 K (ramp‐up) and 650–100 K (ramp‐down) temperature cycle. Several defect levels are detected below the conduction band minimum at 0.41, 0.60, 0.77, 0.96, and 1.17 eV. In the temperature ramp‐down DLTS, the 1.17 eV level disappears, and the 0.60 eV level appears for all Schottky contacts. DFT calculations suggest that rearrangement and dissociation of a single hydrogen from a doubly‐hydrogenated Ga─O divacancy complex occurs during the temperature sweep under bias. The trap level at 0.96 eV only appears after the thermal load for the Ni contact, in contrast to Au and Pt, where it is present without a thermal budget. Temperature‐dependent leakage current (at −4 V) measurements indicate oxidation of Ni, and further thermodynamic analysis suggests alloying of Au‐Ga atoms at the Au/β‐Ga2O3 interface. These studies provide insight into the behavior induced by these common Schottky contacts and the alteration associated with temperature cycling.

Facilitating Near-Infrared Persistent Luminescence in Cr3+ -Doped Gadolinium Gallium Garnets.

Near-infrared persistent luminescence (NIR PersL) materials provide great potential in the fields of night vision, biological imaging, and information encryption. However, among various crystal structures, Cr3+ -dopedgalliumgarnets show inferior PersL property, which turns out to be the bottleneck of their versatile applications. The rational design and facile preparation of high-performance NIR PersL materials are crucial for the emerging applications. In this work, a series of Gd3 Mgx Gex Ga5-2x O12 :Cr3+ (x = 0, 0.25, 0.5, 0.75, 1) is investigated by microwave-assisted solid-state (MASS) approach. Furthermore, by employing chemical composition co-substitution, PersL performance is further improved and the optimum working temperature is adjusted to the lower temperature at 10°C. Trap level distribution of Gd3 Mg0.5 Ge0.5 Ga4 O12 :Cr3+ phosphor is revealed based on the temperature and fading-time dependent PersL and thermoluminescence property. Further study demonstrates the reduction of the bandgap and the trap distribution forwards at shallow-lying trap energy levels. The synergistic effect, from both energy-band manipulation and trap-level optimization, facilitates NIR PersL in Cr3+ -doped gadolinium gallium garnets. These findings confirm the applicability of MASS-based bandgap and defect level engineering for improving the PersL properties in non/inferior-PersL materials. This burgeoning MASS method may facilitate a wide range of PersL materials for various emerging applications.

Revealing the role of defect-induced trap levels in sol–gel-derived TiO2 samples and the synergistic effect of a mixed phase in photocatalytic degradation of organic pollutants

Sol–gel-derived TiO2 samples were synthesized by annealing a xerogel at three different temperatures, namely 350, 550, and 750 °C, which resulted in near-pure anatase, an anatase/rutile mixed phase, and a pure rutile phase, respectively. With the increase in annealing temperature, the average crystallite size increased from ca. 9–48 nm, while the specific surface area decreased from 110.9 to 2.3 m2/g. The mixed-phase sample with a rutile-rich outer layer showed the highest photocatalytic activity, even though the specific surface area of this sample (7.4 m2/g) was much lower than that of the anatase sample (110.9 m2/g). In solar photocatalytic degradation of Methylene Blue dye, the rate constant over this sample (6.25 × 10−2 min−1) was more than three times that over the commercially available photocatalyst Degussa P25 (1.97 × 10−2 min−1). The synergistic increase in the photodegradation performance is attributed to interfacial charge transfer between the anatase and rutile phases. The photocatalytic performances of the anatase and rutile phases can be correlated to the presence of different types of defects. The majority of defects in the anatase sample are shallow levels associated with Vo+, while rutile contains shallow levels related to Ti3+ as well as deep levels corresponding to Vo++.

Charge carrier transport mechanism in plasma polymerized methyl acrylate thin films

Plasma-polymerized methyl acrylate thin films (PPMA) of thicknesses 115 to 290 nm were prepared using a capacitively coupled glow discharge plasma reactor. The current density-voltage (J-V) characteristics of the Aluminum/PPMA/Aluminum sandwich configuration were studied between 0.1 and 75 V over the temperature region from 298 K to 398 K for various thicknesses of PPMA thin films. J-V curves show that the conduction current follows Ohm's law in the low voltage area, but that in the high voltage range, the behavior is attributed to be space charge-limited conduction (SCLC) in PPMA thin films. The free carrier density, the trap density and carrier mobility have been determined to be around 1.77 × 1023 to 5.86 × 1023 m−3, 2.84 × 1024 to 3.77 × 1024 m−3, and 3.87 × 10−18 to 69.7 × 10−18 m2V−1s−1, respectively for various thicknesses of PPMA thin films. For the higher temperature and lower temperature areas, the activation energies were found in the range from 0.60 to 0.84 eV and 0.28 to 0.40 eV, respectively for 5 V in Ohmic region and from 0.61 to 0.98 eV and 0.27 to 0.34 eV, respectively for 60 V in SCLC (Non-Ohmic) region, respectively. It is observed that SCLC mechanism in PPMA thin films is dominated by a single dominant trap level/discrete trap level distribution. The PPMA thin films are promising candidates in manufacturing optoelectronic devices.

Enhanced photocatalytic performance of Cr doped MgO/Bi2O3 nanocomposite for efficient hydroxylation of benzene to phenol under visible-light irradiation

A series of Cr-doped MgO/Bi2O3 (Cr-MgO/Bi2O3) nanocomposites were prepared for the photocatalytic benzene hydroxylation to produce phenol by the visible-light exposure, and the catalyst dosage, solvents and volume ratio of benzene to H2O2 were thoroughly examined. The well-characterized photocatalyst (10% Cr- MgO/Bi2O3) by various physico-chemical and spectroscopic techniques was found to be highly efficient with an optimal phenol selectivity of 98.5% and yield of 13.8%, which were much higher than those obtained from bare Bi2O3, MgO and MgO/Bi2O3. The remarkably improved photocatalytic activity was resulted from the conduction of heterojunction between Bi2O3 and MgO, as well as the generation of a new trapping level within Cr-MgO/Bi2O3 by Cr doping, which greatly accelerated the photogenerated charge carriers separation. This work combining heterojunction conduction and transition metal doping exhibits promising potential for future applications in organic transformation reactions.

The Kinetics of Carrier Trap Parameters in Na8Al6Si6O24(Cl,S)2 Hackmanite.

Tenebrescence has been reported to have a high potential for personal ultraviolet (UV) detection. Color changes can detect UV doses and can also be used as visual sensors for X-rays. Hackmanite is known to exhibit tenebrescence. This study investigated the kinetics of electron-trapping levels contributing to the luminescence of Na8Al6Si6O24(Cl,S)2 hackmanite using thermoluminescence. The glow curves were measured at a heating rate of 5 K/s on hackmanite irradiated with X-rays. The physical parameters of the electron-trapping levels were evaluated by analyzing them using the deconvolution, peak shape, and initial rise methods. The Na8Al6Si6O24(Cl,S)2 hackmanite had at least five trapping levels, with activation energies of 0.78, 1.12, 1.86, 1.26, and 1.18 eV and corresponding peak trap lifetimes of 3.59, 2.71, 1.47, 3.34, and 3.91 s, respectively. The estimated migration time was 15.0 s.

Optimizing dielectric strength and viscosity of synthetic ester with wide bandgap nano-additives

This study explores the potential of insulating oil-based nanofluids as a promising alternative to traditional insulating oils. Specifically, we employ a thermally stimulated depolarization current (TSDC) approach to characterize the effect of trapped charges on the dielectric strength of synthetic ester (SE) based oils (bare SE, SE/Co3O4, and SE/Al2O3). The TSDC findings indicate that nanofluids exhibit higher current density peaks and trap energy levels than bare oil. Nonetheless, the AC breakdown voltage (BDV) of SE oils is significantly enhanced when nanoparticles are well-dispersed. The wide bandgap of Co3O4 and Al2O3 nanoparticles might be responsible for the increase in trap levels, enabling nanofluids to withstand higher AC electric field than pure oils. Additionally, we conduct statistical analyses of the AC BDV values of SE-based oils. Lastly, we find that nanofluids have a lower kinematic viscosity than bare oil.

OR13-05 Longitudinal Changes In Bone Turnover Following Withdrawal Of RANKL Inhibition

Abstract Disclosure: A.S. Kim: None. A. Castro-Martinez: None. V. Taylor: None. J. Center: None. C.M. Girgis: None. P.I. Croucher: None. M.M. Mcdonald: None. Denosumab is an effective osteoporosis treatment, preventing bone loss by inhibiting RANKL. However, stopping denosumab leads to rebound bone mineral density(BMD) loss. This is due to accelerated bone resorption by osteoclasts. Serum bone turnover markers such as P1NP and CTX have been utilised in clinical practice to guide sequential therapy following denosumab discontinuation. However, an optimal strategy has not been established. Understanding the temporal changes in osteoclast activity will guide safe, effective sequential therapy following denosumab discontinuation. We hypothesised that serum TRAP5b, a marker of enzymatic activity of osteoclasts, would be a more useful marker in this context to guide sequential treatment following denosumab discontinuation. Seven-week-old female C57BL/6 mice were treated with 2-weeks of thrice-weekly OPG:Fc(10mg/kg) to inhibit RANKL then withdrawn from therapy (OPG-W) or saline(vehicle). Longitudinal BMD and serum TRAP5b were measured throughout the study. Mice were harvested at weeks 2, 8, 11 and 13 to allow a large volume of serum to be collected to concurrently measure serum TRAP5b and the products of collagen formation and breakdown, serum P1NP and CTX respectively . Following OPG:Fc withdrawal, BMD peaked at week 8 in OPG-W mice (92.94 vs75.09mg/cm2, p<0.0001), started to decline at week 10 and normalised to vehicle levels by week 13. Longitudinally, serum TRAP was suppressed by week 2 (0.05 vs 11.90U/L, p<0.0001) and remained suppressed until week 8, following which serum TRAP levels rose progressively to 64% above vehicle levels at week 12 (17.86 vs 10.92U/L, p<0.0001). The rise in TRAP between weeks 8 to 10 preceded the decline in BMD.Serum TRAP was significantly elevated in OPG-W mice at week 11 (15.45 vs 11.46U/L, p=0.01) whereas serum P1NP and CTX remained equivalent to vehicle levels. Serum TRAP, P1NP and CTX were significantly higher in OPG-W mice at week 13 by which time BMD had reached vehicle levels. Our findings show that rebound decline in BMD has already occurred by the time bone turnover markers used in clinical practice (P1NP and CTX) rise above vehicle levels. A significant overshoot in serum TRAP occurs earlier and prior to bone loss and may better inform sequential therapy following denosumab discontinuation. Presentation: Friday, June 16, 2023

Thickness dependent studies on p-type K-doped ZnS nanostructured films grown via colloid-based solution route for ambipolar optoelectronic applications

Potassium-doped Zinc Sulphide (K:ZnS) nanostructured films were deposited on silica substrates using a colloid-based solution method, with varying thicknesses from 3 to 6 coats. The films exhibited p-type electrical conductivity and favorable optical properties for ambipolar and optoelectronic device fabrication. X-ray analysis confirmed a polycrystalline cubic phase in all the films, with crystallite sizes of 7–27 nm. Scanning electron micrographs revealed spherical globular grains of sizes 1.20–2.84 μm, leading to improved compactness with thicker films. UV/VIS analysis demonstrated a red-shifted band gap with increasing thickness. Photoluminescence under UV excitation revealed a peak at 477 nm attributed to K-induced trap levels. The electrical resistivity (1.34–6.00) × 102 Ω⋅cm, carrier concentration (4.63–13.33) × 1015 cm−3, and mobility (2.25–3.50) cm2/V·s varied with film thickness. The minimum resistivity of 1.34 × 102 (Ω⋅cm), maximum conductivity of 7.46 × 10−3 (Ω−1⋅cm−1), and highest mobility of 3.50 (cm2/V·s) were obtained for K:ZnS-6 film.