Effect of substrate temperature on the properties of copper nitride thin films deposited by reactive magnetron sputtering

Cho, Shinho

doi:10.1016/j.cap.2012.05.033

Cited by 7 publications

(5 citation statements)

References 18 publications

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“…Its main attraction is that it is a non-toxic, metastable, and low-cost semiconducting material with earth-abundant elements and high stability at room temperature (RT). In addition, different studies have reported a wide range of band gap energy values, i.e., from 0.8 eV to 1.9 eV, which are easily achievable by controlling the deposition conditions [1,2]. The density functional theory (DFT) calculations, on the other hand, predict a relatively smaller E g , ranging from 0.23 eV to 1.0 eV [3].…”

Section: Introductionmentioning

confidence: 99%

Effect of Argon on the Properties of Copper Nitride Fabricated by Magnetron Sputtering for the Next Generation of Solar Absorbers

et al. 2022

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Copper nitride, a metastable semiconductor material with high stability at room temperature, is attracting considerable attention as a potential next-generation earth-abundant thin-film solar absorber. Moreover, its non-toxicity makes it an interesting eco-friendly material. In this work, copper nitride films were fabricated using reactive radio frequency (RF) magnetron sputtering at room temperature, 50 W of RF power, and partial nitrogen pressures of 0.8 and 1.0 on glass and silicon substrates. The role of argon in both the microstructure and the optoelectronic properties of the films was investigated with the aim of achieving a low-cost absorber material with suitable properties to replace the conventional silicon in solar cells. The results showed a change in the preferential orientation from (100) to (111) planes when argon was introduced in the sputtering process. Additionally, no structural changes were observed in the films deposited in a pure nitrogen environment. Fourier transform infrared (FTIR) spectroscopy measurements confirmed the presence of Cu–N bonds, regardless of the gas environment used, and XPS indicated that the material was mainly N-rich. Finally, optical properties such as band gap energy and refractive index were assessed to establish the capability of this material as a solar absorber. The direct and indirect band gap energies were evaluated and found to be in the range of 1.70–1.90 eV and 1.05−1.65 eV, respectively, highlighting a slight blue shift when the films were deposited in the mixed gaseous environment as the total pressure increased.

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Section: Introductionmentioning

confidence: 99%

Effect of Argon on the Properties of Copper Nitride Fabricated by Magnetron Sputtering for the Next Generation of Solar Absorbers

et al. 2022

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“…Cu 3 N has been obtained by a variety of methods including sputtering, ,− molecular beam epitaxy, atomic layer deposition, , and pulsed laser deposition. , Recently, Matsuzaki et al have obtained Cu 3 N from Cu under NH 3 and O 2 between 500 and 800 °C. However, in the past, most have obtained Cu 3 N by sputtering of Cu under N 2 in conjunction with Ar, which enables control over its stoichiometry.…”

Section: Introductionmentioning

confidence: 99%

Observation of the Direct Energy Band Gaps of Defect-Tolerant Cu₃N by Ultrafast Pump-Probe Spectroscopy

et al. 2020

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Cu 3 N with a cubic crystal structure has been prepared from Cu on fused SiO 2 under a flow of NH 3 :O 2 between 400 and 600 °C. All Cu 3 N layers exhibited distinct maxima in differential transmission at ∼500, 550, and 630, 670 nm with the same spectral structure and shape on a ps timescale as shown by ultrafast pump-probe spectroscopy. We show that the maxima at 630 (≡1.97 eV) and 670 nm (≡1.85 eV) correspond to the M and R direct energy band gaps of Cu 3 N, in excellent agreement with density functional theory calculations of the electronic band structure. These findings are corroborated further by the fact that Cu 3 N as-deposited by reactive sputtering under 100% N 2 at 25 °C and 10 −2 mbar did not exhibit a fine spectral structure due to a smeared density of states, poor crystallinity, and a high density of defects, but annealing under NH 3 :H 2 at 300 °C revealed a similar spectral structure to Cu 3 N obtained from Cu under NH 3 :O 2 . In contrast to the above, we suggest that the peaks at 500 (≡2.48 eV) and 550 nm (≡2.25 eV) might correspond to the M and R direct gaps of certain regions of Cu 3 N under strain that changes the lattice constant and band gap. We discuss the charge carrier generation and recombination mechanisms in terms of Cu interstitials and vacancies that are known to be energetically located near the band edges, thus allowing the observation of the direct energy band gaps in this defect tolerant semiconductor.

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“…Cu 3 N was found to exhibit either n-type conduction 13,14 or quasi-metallic behavior, 11,15 with carrier concentration or conductivity being directly proportional to substrate temperature during growth. Theoretical calculations later showed that Cu 3 N has a band structure with anti-bonding states at the valence band maximum (VBM), opposite to that of conventional semiconductors with bonding states at the VBM.…”

Section: Introductionmentioning

confidence: 99%

“…Prior work on Cu 3 N has focused on characterizing properties such as decomposition temperature, [7][8][9] reflectivity, [10][11][12] and conductivity 11 as a function of changing deposition parameters. Cu 3 N was found to exhibit either n-type conduction 13,14 or quasi-metallic behavior, 11,15 with carrier concentration or conductivity being directly proportional to substrate temperature during growth. Theoretical calculations later showed that Cu 3 N has a band structure with antibonding states at the valence band maximum (VBM), opposite to that of conventional semiconductors with bonding states at the VBM.…”

Section: Introductionmentioning

confidence: 99%

Understanding and control of bipolar self-doping in copper nitride

Fioretti

Schwartz

Vinson

et al. 2016

Journal of Applied Physics

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Semiconductor materials that can be doped both n-type and p-type are desirable for diode-based applications and transistor technology. Copper nitride (Cu3N) is a metastable semiconductor with a solar-relevant bandgap that has been reported to exhibit bipolar doping behavior. However, deeper understanding and better control of the mechanism behind this behavior in Cu3N is currently lacking in the literature. In this work, we use combinatorial growth with a temperature gradient to demonstrate both conduction types of phase-pure, sputter-deposited Cu3N thin films. Room temperature Hall effect and Seebeck effect measurements show n-type Cu3N with an electron density of 1017 cm−3 for low growth temperature (≈ 35 °C) and p-type with a hole density between 1015 cm−3 and 1016 cm−3 for elevated growth temperatures (50 °C to 120 °C). Mobility for both types of Cu3N was ≈ 0.1 cm2/Vs to 1 cm2/V. Additionally, temperature-dependent Hall effect measurements indicate that ionized defects are an important scattering mechanism in p-type films. By combining X-ray absorption spectroscopy and first-principles defect theory, we determined that VCu defects form preferentially in p-type Cu3N while Cui defects form preferentially in n-type Cu3N; suggesting that Cu3N is a compensated semiconductor with conductivity type resulting from a balance between donor and acceptor defects. Based on these theoretical and experimental results, we propose a kinetic defect formation mechanism for bipolar doping in Cu3N, that is also supported by positron annihilation experiments. Overall, the results of this work highlight the importance of kinetic processes in the defect physics of metastable materials, and provide a framework that can be applied when considering the properties of such materials in general.

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Effect of substrate temperature on the properties of copper nitride thin films deposited by reactive magnetron sputtering

Cited by 7 publications

References 18 publications

Effect of Argon on the Properties of Copper Nitride Fabricated by Magnetron Sputtering for the Next Generation of Solar Absorbers

Effect of Argon on the Properties of Copper Nitride Fabricated by Magnetron Sputtering for the Next Generation of Solar Absorbers

Observation of the Direct Energy Band Gaps of Defect-Tolerant Cu₃N by Ultrafast Pump-Probe Spectroscopy

Understanding and control of bipolar self-doping in copper nitride

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Effect of substrate temperature on the properties of copper nitride thin films deposited by reactive magnetron sputtering

Cited by 7 publications

References 18 publications

Effect of Argon on the Properties of Copper Nitride Fabricated by Magnetron Sputtering for the Next Generation of Solar Absorbers

Effect of Argon on the Properties of Copper Nitride Fabricated by Magnetron Sputtering for the Next Generation of Solar Absorbers

Observation of the Direct Energy Band Gaps of Defect-Tolerant Cu3N by Ultrafast Pump-Probe Spectroscopy

Understanding and control of bipolar self-doping in copper nitride

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Observation of the Direct Energy Band Gaps of Defect-Tolerant Cu₃N by Ultrafast Pump-Probe Spectroscopy