Thermal evaporated Copper Iodide (CuI) thin films: A note on the disorder evaluated through the temperature dependent electrical properties

Kaushik, Deepak Kumar; Selvaraj, M.; Ramu, S.; Subrahmanyam, A.

doi:10.1016/j.solmat.2017.02.030

Cited by 96 publications

(84 citation statements)

References 47 publications

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“…The weak temperature dependence of the carrier density of CuI films was found to show a simple thermally activated behavior with small activation energy . In a recent report, hopping transport is claimed to be the dominant transport mechanism in CuI thin films . However, only one single sample was investigated there and the several dependencies of the variable range hopping process were limited to narrow temperature ranges.…”

Section: Introductionsupporting

confidence: 73%

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Suppression of Grain Boundary Scattering in Multifunctional p‐Type Transparent γ‐CuI Thin Films due to Interface Tunneling Currents

Kneiß

Yang

Barzola‐Quiquia

et al. 2018

Adv Materials Inter

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Transparent p‐type conductive γ‐CuI thin films typically exhibit unexpectedly high hole mobilities in the range of 10 cm2 V−1 s−1 even when heavily textured. To explain this phenomenon, the transport properties of such thin films are investigated. The temperature‐dependent resistivities of the textured (111)‐oriented films with different carrier concentration are fitted using the fluctuation‐induced tunneling conductivity (FITC) model in series with a power law. The FITC model describes barriers at the grain boundaries whereas the power law considers the scattering in the metallic interior of the grains. Magnetoresistance measurements performed on a reactively DC‐sputtered thin film at low temperatures (T < 8 K) suggest a 2D weak antilocalization effect with phase coherence lengths of about 50 nm. This is corroborated by a typical logarithmic temperature dependence of the zero‐field conductance. An n‐type inversion layer or a defect band at the interfaces of the grains as origin of the 2D carrier system and the barriers at the grain boundaries is proposed. This leads to a conclusive description of the electrical transport properties of γ‐CuI thin films and explains the high hole mobilities which are due to a suppressed backscattering at the grain boundaries in the presence of tunneling channels.

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Section: Introductionsupporting

confidence: 73%

“…A recent report on thermally evaporated CuI thin films determined the surface work function with Kelvin probe measurements to be ≈ 4.7 eV . Together with the band lineup given in ref.…”

Section: Resultsmentioning

confidence: 64%

Suppression of Grain Boundary Scattering in Multifunctional p‐Type Transparent γ‐CuI Thin Films due to Interface Tunneling Currents

Kneiß

Yang

Barzola‐Quiquia

et al. 2018

Adv Materials Inter

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show abstract

“…45 We were not able to observe the longitudinal-optical (LO) mode at 140 cm −1 , which can be interpreted by the reason that the LO peak may be sub-merged in the broad TO peak resulting from the existence of the disorder in the structure of γ-CuI. 46 A spatially resolved mapping of the Raman signal (122 cm −1 ) shows highly uniform contrast throughout the entire nanosheet ( Fig. 2e), suggesting highly uniform crystalline quality across the entire nanosheet.…”

Section: Resultsmentioning

confidence: 93%

Synthesis of ultrathin two-dimensional nanosheets and van der Waals heterostructures from non-layered γ-CuI

et al. 2018

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Two-dimensional (2D) nanosheets have attracted considerable recent interest for their atomically thin geometry and unique thickness-dependent electronic properties. The 2D nanosheets studied to date are generally limited to intrinsically layered materials, in which the covalently bonded atomic layers are held together by weak van der Waals forces and can be readily exfoliated to single or few-atom thick nanosheets. To prepare 2D nanosheets from non-layered materials can greatly expand the scope of 2D materials, but is much less straightforward. Here, we report the successful synthesis of ultrathin nanosheets from nonlayered γ-CuI on SiO 2 /Si substrate using a facile physical vapor deposition process. The resulting γ-CuI nanosheets display a triangular and hexagonal geometry with the lateral dimension up to 5 μm and thickness down to 1 nm. Raman spectroscopy, X-ray diffraction, and transmission electron microscopy studies demonstrate the resulting nanosheets retain single-crystalline γ-CuI phase. Additionally, we further show the γ-CuI nanosheets can be readily grown on other 2D materials (e.g., 2D-WSe 2 , 2D-WS 2) to form van der Waals heterostructures (vdWHs). Optical microscopy images and Raman intensity mappings confirm the formation of γ-CuI/WS 2 and γ-CuI/WSe 2 vertical heterostructures. The electrical transport studies show that γ-CuI nanosheets exhibit a low resistivity of~0.3 Ω cm and γ-CuI/WS 2 vertical heterostructures display a p-n diode behavior with distinct current rectification. The synthesis of γ-CuI nanosheets and heterostructures open a pathway to ultrathin nanosheets and van der Waals heterostructures from non-layered materials and could open up exciting opportunities in electronics and optoelectronics.

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“…The TiO 2 -coated FTO showed a tiny peak (*) at ≈25.7°, which can be assigned to the (101) plane of TiO 2 . This distinct peak can be attributed to the (111) reflection of the polycrystalline γ-phase of CuI with a zinc-blende face-centered cubic structure, [30] along with three distinct FTO diffraction peaks. This distinct peak can be attributed to the (111) reflection of the polycrystalline γ-phase of CuI with a zinc-blende face-centered cubic structure, [30] along with three distinct FTO diffraction peaks.…”

mentioning

confidence: 99%

p‐Type CuI Islands on TiO₂ Electron Transport Layer for a Highly Efficient Planar‐Perovskite Solar Cell with Negligible Hysteresis

Byranvand

Kim

Song

et al. 2017

Advanced Energy Materials

129

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Perovskite solar cells (PSCs) have attracted much attention owing to their high power conversion efficiencies (PCEs) and relatively low fabrication costs compared with conventional silicon-based solar cells. [1,2] In a planar n-i-p-type PSC, a perovskite layer is sandwiched between a fluorine-doped tin oxide (FTO) glass substrate with an electron transport layer (ETL) and a hole transport layer (HTL) with metal electrode, respectively. The ETL plays an important role in electron extraction and hole blocking. A compact TiO 2 layer is widely used [3] as the ETL in PSCs owing to its excellent optical transmittance and superior chemical stability at high temperatures in air, although various ETL materials including metallic salts, [4] transition metal oxides, [5,6] or organic materials [7,8] have been reported. In addition, the TiO 2 compact layer can be easily prepared from its precursor solution via a sol-gel process. By employing such Compact TiO 2 is widely used as an electron transport material in planarperov skite solar cells. However, TiO 2 -based planar-perovskite solar cells exhibit low efficiencies due to intrinsic problems such as the unsuitable conduction band energy and low electron extraction ability of TiO 2 . Herein, the planar TiO 2 electron transport layer (ETL) of perovskite solar cells is modified with ionic salt CuI via a simple one-step spin-coating process. The p-type nature of the CuI islands on the TiO 2 surface leads to modification of the TiO 2 band alignment, resulting in barrier-free contacts and increased open-circuit voltage. It is found that the polarity of the CuI-modified TiO 2 surface can pull electrons to the interface between the perovskite and the TiO 2 , which improves electron extraction and reduces nonradiative recombination. The CuI solution concentration is varied to control the electron extraction of the modified TiO 2 ETL, and the optimized device shows a high efficiency of 19.0%. In addition, the optimized device shows negligible hysteresis, which is believed to be due to the removal of trap sites and effective electron extraction by CuI-modified TiO 2 . These results demonstrate the hitherto unknown effect of p-type ionic salts on electron transport material.

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Thermal evaporated Copper Iodide (CuI) thin films: A note on the disorder evaluated through the temperature dependent electrical properties

Cited by 96 publications

References 47 publications

Suppression of Grain Boundary Scattering in Multifunctional p‐Type Transparent γ‐CuI Thin Films due to Interface Tunneling Currents

Suppression of Grain Boundary Scattering in Multifunctional p‐Type Transparent γ‐CuI Thin Films due to Interface Tunneling Currents

Synthesis of ultrathin two-dimensional nanosheets and van der Waals heterostructures from non-layered γ-CuI

p‐Type CuI Islands on TiO₂ Electron Transport Layer for a Highly Efficient Planar‐Perovskite Solar Cell with Negligible Hysteresis

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Thermal evaporated Copper Iodide (CuI) thin films: A note on the disorder evaluated through the temperature dependent electrical properties

Cited by 96 publications

References 47 publications

Suppression of Grain Boundary Scattering in Multifunctional p‐Type Transparent γ‐CuI Thin Films due to Interface Tunneling Currents

Suppression of Grain Boundary Scattering in Multifunctional p‐Type Transparent γ‐CuI Thin Films due to Interface Tunneling Currents

Synthesis of ultrathin two-dimensional nanosheets and van der Waals heterostructures from non-layered γ-CuI

p‐Type CuI Islands on TiO2 Electron Transport Layer for a Highly Efficient Planar‐Perovskite Solar Cell with Negligible Hysteresis

Contact Info

Product

Resources

About

p‐Type CuI Islands on TiO₂ Electron Transport Layer for a Highly Efficient Planar‐Perovskite Solar Cell with Negligible Hysteresis