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Effects of annealing conditions on the properties of SnO films deposited by e-beam evaporation process
Materials Letters 257 (2019) 126737
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Effects of annealing conditions on the properties of SnO films deposited by e-beam evaporation process Ling Pan, Wenbiao Li, Shi-E Yang, Jinhao Zang, Haizhong Guo, Tianyu Xia, Weixia Shen, Yongsheng Chen ⇑ Key Lab of Material Physics, Department of Physics and Engineering, Zhengzhou University, Zhengzhou 450052, PR China
a r t i c l e
i n f o
Article history: Received 19 August 2019 Received in revised form 18 September 2019 Accepted 22 September 2019 Available online 23 September 2019 Keywords: SnO films E-beam evaporation Annealing Hall measurements
a b s t r a c t The SnO thin films have been deposited on quartz glass substrates using an e-beam evaporation system at room temperature and different post-deposition thermal treatments have been carried out. In case of annealing in air, n-type polycrystalline SnO films are obtained after annealing at 300 °C and 400 °C, respectively. For the 500 °C annealed film, SnO2 phase is generated due to the strong oxidation. However, when annealed in vacuum, pure p-type polycrystalline SnO films are produced. The feasible and controllable methods of p- and n-type SnO films contributes to the development of high performance devices. Ó 2019 Elsevier B.V. All rights reserved.
1. Introduction SnO has attracted more attention for electronic and optoelectronic device applications [1–4]. It generally exhibits p-type conductivity with a large optical bandgaps (2.7–3.4 eV) due to the low defect-formation energy of Sn vacancies [5]. More interesting, SnO has shown a bipolar conductivity [6–8], which broadens the application range of materials for designing new alternatives. Hosono et al. fabricated n-type SnO films with about 0.8 cation% Sb using SnO targets [7]. Hayashi et al. [8] prepared undoped n-type and p-type SnO thin films by carefully controlling oxygen partial pressure. Therefore, it is very urgent to explore an effective and feasible method for preparing p- and n-type SnO films. In this paper, p- and n-type SnO films are successfully fabricated by changing the annealing conditions, which is favorable to design of novel devices.
2. Experiments Samples have been deposited onto highly cleaned quartz substrates using electron beam evaporation system using SnO2 powder target. A vacuum pressure of ~4 10 4 Pa was maintained during the evaporation process. The deposition process is carried ⇑ Corresponding author. E-mail address: [email protected] (Y. Chen). https://doi.org/10.1016/j.matlet.2019.126737 0167-577X/Ó 2019 Elsevier B.V. All rights reserved.
out at room temperature. Then the deposited samples with thickness of 120 nm are subjected to thermal annealing at 100–500 °C for 30 min in a vacuum chamber with base pressure of 4.0 10 4 Pa, or in air using a muffle furnace. The properties of the sample were characterized by X-ray diffraction (XRD, X’pert PRO), UV–vis–NIR spectrophotometer (HITACHI-UH4150), Hall-effect measurement setup (ET-9000) and micro-Raman spectrometer (RENISHAW). All measurements were performed at room temperature. 3. Results and discussion Fig. 1 shows XRD patterns of samples before and after annealing in air and vacuum, respectively. For the as-prepared sample, broad diffraction peaks at ~21.7° and ~28.7° correspond to the quartz substrate (Fig. S1) and SnO film respectively, indicating that the film deposited at room temperature is amorphous. After annealing at 250 °C in air (Fig. 1a), peaks at 18.3°, 29.9°, 33.3° and 37.1° belonging to SnO [PDF#06-0395] are appeared. With the increase of the annealing temperature, the intensities of peaks increase, suggesting that the crystallinity of the films is enhanced [9,10]. However, when annealing temperature reaches 500 °C, new peaks of rutile phase SnO2 [PDF#01-072-1147] are generated due to the strong oxidation reaction. When annealed in vacuum (Fig. 1b), the film crystallizes rapidly once the temperature reaches 200 °C. The intensities of peaks increase with annealing temperature, and a preferred crystalline
2
L. Pan et al. / Materials Letters 257 (2019) 126737
Fig. 1. XRD spectra of SnO thin films before and after annealing in air (a) and vacuum (b).
orientation along (0 0 1) direction is observed. It is reported that SnO phase is stable up to 270 °C [11] and partial decomposition of SnO in to Sn and SnO2 at 300 °C [12–14]. In our study, pure SnO are prepared after annealing at 500 °C, suggesting that film is more stable than powder due to an effect of reduced surface area [15,16]. Raman spectra (Fig. 2) of samples are consistent with XRD results in Fig. 1. The peaks at ~110 cm 1 and ~210 cm 1 correspond to the vibrational modes of Eg and A1g of SnO, respectively. Raman spectrum fingerprint has close relationship with the grain orientation [17], and the strong intensities of 210 cm 1 peaks for the films after vacuum annealing is in agreement with the (1 0 1) preferred crystalline orientation in Fig. 1b. Fig. 3 shows the absorption spectra of films before and after annealing at different annealing temperature. After annealing in air, the absorption is enhanced in the range of 350 nm to 450 nm with the increase of annealing temperature. From the plot of (aht)2 as a function of photon energy (ht) (Fig. S2), the bandgap (Eg) is deduced (Table 1). Eg decreases slightly with the increase
Fig. 2. Raman spectra of samples after annealing in air (a) and vacuum (b).
of annealing temperature, but sharply increases at temperature of 500 °C due to the formation of SnO2. The color of films shown in insets is changed from light yellow to dark yellow and then to white with the increase of the annealing temperature. When annealed in vacuum, the absorption in the range of short wavelength increases with the increase of annealing temperature, and reaches saturation, but Eg, deduced from Fig. S3, decreases slightly. Meanwhile, the color of films is changed from yellowish to dark yellow. The electrical properties of the films after annealing are studied by Hall effect measurement (Table 1). For the film annealed at 500 °C in air, n-type conductivity is obtained due to the formation of SnO2 phase. The exciting thing is that after annealing at moderate temperature, such as 300 °C or 400 °C, pure SnO films with ntype conduction are prepared, in which no evidence of metallic tin precipitates is observed, in contrast to Ref. [18]. The Hall mobility of ~5 cm2V 1s 1 is close to the reported values for n-SnO, 0.57 cm2V 1s 1 to 11 cm2V 1s 1 [8]. The formation mechanism of n-type SnO films during air annealing is shown in Fig. 4.
3
L. Pan et al. / Materials Letters 257 (2019) 126737
At 300–400 °C, O atoms diffuse into the gap of Sn-O-Sn layers to capture the Sn 5 s2 electrons without disturbing the layered structure, leading to the generation of Sn3+ state (Fig. S4) [19]. Another 5 s2 electron of Sn3+ becomes free electron. Once the concentration of free electrons exceeds that of holes, the film changes from p-type to n-type. However, at 500 °C, structural reconstruction is caused by intense oxidation, and SnO2 phase formed. When annealed in vacuum, p-type films are obtained at temperature of 200 °C to 500 °C with mobilities of 1.10–3.28 cm2V 1s 1, in accordance with the previous reports [8,15,20–22]. These studies laid the foundation for the subsequent construction of homogeneous junction and characteristic analysis, especially stability [23].
4. Conclusion In summary, SnO thin films have been synthesized by e-beam evaporation at room temperature, followed annealing in air and vacuum, respectively. With the increase of annealing temperature in air, the structure transforms from amorphous SnO into polycrystalline SnO and then into polycrystalline SnO2 phase. Interestingly, n-type SnO films are obtained after annealing at 300 °C and 400 °C, respectively. However, in case of annealing in vacuum, phase transition from amorphous SnO to polycrystalline SnO is found with the increase of annealing temperature, without the formation of SnO2. And the annealed films present p-type conductivity. So, this feasible and simple method for the fabrication of p- and n-type SnO films, which will contribute to expand their application field.
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Appendix A. Supplementary data
Fig. 3. Absorption spectra of SnO thin films before and after annealing in air (a) and vacuum (b). Insets show the photos of films.
Supplementary data to this article can be found online at https://doi.org/10.1016/j.matlet.2019.126737.
Table 1 Properties of films after annealing in air and vacuum, respectively. Conditions
Temperature ( )
Eg (eV)
p/n type
Resistivity (Xcm)
Carrier density (cm
as-deposited air
25 250 300 400 500 100 200 300 400 500
2.81 2.79 2.76 2.7 3.12 2.8 2.77 2.75 2.73 2.72
– – n n n – p p p p
– – 0.17 0.18 0.14 – 9.58 5.09 7.36 10.30
– – 5.63 1018 7.70 1018 4.10 1019 – 5.93 1017 9.16 1017 2.91 1017 1.85 1017
vacuum
3
)
Mobility (cm2v – – 6.63 4.53 1.08 – 1.10 1.34 2.92 3.28
1
s
1
)
4
L. Pan et al. / Materials Letters 257 (2019) 126737
Fig. 4. Formation mechanism of n-type SnO films during air annealing.
References [1] H. Luo, L. Liang, H. Cao, Carrier trapping anisotropy in ambipolar SnO thin-film transistors, Solid-State Electron. 129 (2017) 88–92. [2] A. Sharma, M. Varshney, K.D. Verma, Y. Kumar, R. Kumar, Structural and surface microstructure evolutions in SnO thin films under ion irradiation, Nucl. Instrum. Methods Phys. Res., Sect. B 308 (2013) 15–20. [3] M. Batzill, U. Diebold, The surface and materials science of tin oxide, Prog. Surf. Sci. 79 (2005) 47–154. [4] R. Barros, K.J. Saji, J.C. Waerenborgh, P. Barquinha, L. Pereira, E. Carlos, R. Martins, E. Fortunato, Role of structure and composition on the performances of p-type tin oxide thin-film transistors processed at low-temperatures, Nanomaterials 9 (2019) 320. [5] S.H. Kwon, H.J. Joo, H.I. Kwon, Effects of simultaneous ultraviolet and thermal treatments on physical and chemical properties of RF-sputtered p-type SnO thin-films, Ceram. Int. 44 (2018) 20883–20889. [6] N.F. Quackenbush, J.P. Allen, D.O. Scanlon, S. Sallis, J.A. Hewlett, A.S. Nandur, B. Chen, K.E. Smith, C. Weiland, D.A. Fischer, J.C. Woicik, B.E. White, G.W. Watson, L.F.J. Piper, Origin of the Bipolar Doping Behavior of SnO from X-ray Spectroscopy and Density Functional Theory, Chem. Mater. 25 (2013) 3114– 3123. [7] A.H.-T. Nguyen, M.-C. Nguyen, J. Choi, S. Han, J. Kim, R. Choi, Electrical performance enhancement of p-type tin oxide channel thin film transistor using aluminum doping, Thin Solid Films 641 (2017) 24–27. [8] H. Hayashi, S. Katayama, R. Huang, K. Kurushima, I. Tanaka, Selective fabrication of n- and p-type SnO films without doping, Phys. Status Solidi (RRL) – Rapid Res. Lett. 9 (2015) 192–196. [9] S.S. Lin, S.Y. Fan, Y.S. Tsai, Effects of annealing on wettability and physical properties of SnO thin films deposited at low RF power densities, Ceram. Int. 43 (2017) 1802–1808. [10] P.B. Barna, M. Adamik, Fundamental structure forming phenomena of polycrystalline films and the structure zone models, Thin Solid Films 317 (1998) 27–33. [11] G.H. Moh, Tin,, containing mineral systems. Part I: The Sn–Fe–S–O systems and mineral assemblages in ores, Chem. Erde. 33 (1974) 243–275.
[12] J.C. Platteeuw, G. Meyer, The system tin+oxygen, Trans. Faraday Soc. 52 (1955) 1066–1073. [13] H. Giefers, F. Porsch, G. Wortmann, Kinetics of the disproportionation of SnO, Solid State Ionics 176 (2005) 199–207. [14] J.H. Shin, J.Y. Song, Y.H. Kim, H.M. Park, Low temperature and self-catalytic growth of tetragonal SnO nanobranch, Mater. Lett. 64 (2010) 1120–1122. [15] L.Y. Liang, Z.M. Liu, H.T. Cao, X.Q. Pan, Microstructural, optical, and electrical properties of SnO thin films prepared on quartz via a two-step method, ACS Appl. Mater. Interfaces 2 (2010) 1060–1065. [16] L.Y. Liang, Z.M. Liu, H.T. Cao, Y.Y. Shi, X.L. Sun, Z. Yu, A.H. Chen, H.Z. Zhang, Y.Q. Fang, Improvement of phase stability and accurate determination of optical constants of SnO thin films by using Al2O3 capping layer, ACS Appl. Mater. Interfaces 2 (2010) 1565–1568. [17] Q. Liu, L. Liang, H. Cao, H. Luo, H. Zhang, J. Li, X. Li, F. Deng, Tunable crystallographic grain orientation and Raman fingerprints of polycrystalline SnO thin films, J. Mater. Chem. C 3 (2015) 1077–1081. [18] J.A. Caraveo-Frescas, P.K. Nayak, H.A. Al-Jawhari, D.B. Granato, U. Schwingenschlögl, H.N. Alshareeft, Record mobility in transparent p-type tin monoxide films and devices by phase engineering, Acs Nano 7 (6) (2013) 5160–5167. [19] X.Q. Pan, L. Fu, Tin oxide thin films grown on the (1012) sapphire substrate, J. Electroceram. 7 (2001) 35–46. [20] Y. Ogo, H. Hiramatsu, K. Nomura, H. Yanagi, T. Kamiya, M. Kimura, M. Hirano, H. Hosono, Tin monoxide as an s-orbital-based p-type oxide semiconductor: electronic structures and TFT application, Phys. Status Solidi A 206 (2009) 2187–2191. [21] Y. Ogo, H. Hiramatsu, K. Nomura, H. Yanagi, T. Kamiya, M. Hirano, H. Hosono, P-channel thin-film transistor using p-type oxide semiconductor, Appl. Phys. Lett. 93 (2008) 032113. [22] W. Guo, L. Fu, Y. Zhang, K. Zhang, L.Y. Liang, Z.M. Liu, H.T. Cao, X.Q. Pan, Microstructure, optical, and electrical properties of p-type SnO thin films, Appl. Phys. Lett. 96 (2010) 042113. [23] R. Sathyamoorthy, K.M. Abhirami, B. Gokul, S. Gautam, K.H. Chae, K. Asokan, Fabrication of p-n Junction Diode Using SnO/SnO2 Thin Films and Its Device Characteristics, Electron. Mater. Lett. 10 (2014) 743–747.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Effects of annealing conditions on the properties of SnO films deposited by e-beam evaporation process Ling Pan, Wenbiao Li, Shi-E Yang, Jinhao Zang, Haizhong Guo, Tianyu Xia, Weixia Shen, Yongsheng Chen ⇑ Key Lab of Material Physics, Department of Physics and Engineering, Zhengzhou University, Zhengzhou 450052, PR China
a r t i c l e
i n f o
Article history: Received 19 August 2019 Received in revised form 18 September 2019 Accepted 22 September 2019 Available online 23 September 2019 Keywords: SnO films E-beam evaporation Annealing Hall measurements
a b s t r a c t The SnO thin films have been deposited on quartz glass substrates using an e-beam evaporation system at room temperature and different post-deposition thermal treatments have been carried out. In case of annealing in air, n-type polycrystalline SnO films are obtained after annealing at 300 °C and 400 °C, respectively. For the 500 °C annealed film, SnO2 phase is generated due to the strong oxidation. However, when annealed in vacuum, pure p-type polycrystalline SnO films are produced. The feasible and controllable methods of p- and n-type SnO films contributes to the development of high performance devices. Ó 2019 Elsevier B.V. All rights reserved.
1. Introduction SnO has attracted more attention for electronic and optoelectronic device applications [1–4]. It generally exhibits p-type conductivity with a large optical bandgaps (2.7–3.4 eV) due to the low defect-formation energy of Sn vacancies [5]. More interesting, SnO has shown a bipolar conductivity [6–8], which broadens the application range of materials for designing new alternatives. Hosono et al. fabricated n-type SnO films with about 0.8 cation% Sb using SnO targets [7]. Hayashi et al. [8] prepared undoped n-type and p-type SnO thin films by carefully controlling oxygen partial pressure. Therefore, it is very urgent to explore an effective and feasible method for preparing p- and n-type SnO films. In this paper, p- and n-type SnO films are successfully fabricated by changing the annealing conditions, which is favorable to design of novel devices.
2. Experiments Samples have been deposited onto highly cleaned quartz substrates using electron beam evaporation system using SnO2 powder target. A vacuum pressure of ~4 10 4 Pa was maintained during the evaporation process. The deposition process is carried ⇑ Corresponding author. E-mail address: [email protected] (Y. Chen). https://doi.org/10.1016/j.matlet.2019.126737 0167-577X/Ó 2019 Elsevier B.V. All rights reserved.
out at room temperature. Then the deposited samples with thickness of 120 nm are subjected to thermal annealing at 100–500 °C for 30 min in a vacuum chamber with base pressure of 4.0 10 4 Pa, or in air using a muffle furnace. The properties of the sample were characterized by X-ray diffraction (XRD, X’pert PRO), UV–vis–NIR spectrophotometer (HITACHI-UH4150), Hall-effect measurement setup (ET-9000) and micro-Raman spectrometer (RENISHAW). All measurements were performed at room temperature. 3. Results and discussion Fig. 1 shows XRD patterns of samples before and after annealing in air and vacuum, respectively. For the as-prepared sample, broad diffraction peaks at ~21.7° and ~28.7° correspond to the quartz substrate (Fig. S1) and SnO film respectively, indicating that the film deposited at room temperature is amorphous. After annealing at 250 °C in air (Fig. 1a), peaks at 18.3°, 29.9°, 33.3° and 37.1° belonging to SnO [PDF#06-0395] are appeared. With the increase of the annealing temperature, the intensities of peaks increase, suggesting that the crystallinity of the films is enhanced [9,10]. However, when annealing temperature reaches 500 °C, new peaks of rutile phase SnO2 [PDF#01-072-1147] are generated due to the strong oxidation reaction. When annealed in vacuum (Fig. 1b), the film crystallizes rapidly once the temperature reaches 200 °C. The intensities of peaks increase with annealing temperature, and a preferred crystalline
2
L. Pan et al. / Materials Letters 257 (2019) 126737
Fig. 1. XRD spectra of SnO thin films before and after annealing in air (a) and vacuum (b).
orientation along (0 0 1) direction is observed. It is reported that SnO phase is stable up to 270 °C [11] and partial decomposition of SnO in to Sn and SnO2 at 300 °C [12–14]. In our study, pure SnO are prepared after annealing at 500 °C, suggesting that film is more stable than powder due to an effect of reduced surface area [15,16]. Raman spectra (Fig. 2) of samples are consistent with XRD results in Fig. 1. The peaks at ~110 cm 1 and ~210 cm 1 correspond to the vibrational modes of Eg and A1g of SnO, respectively. Raman spectrum fingerprint has close relationship with the grain orientation [17], and the strong intensities of 210 cm 1 peaks for the films after vacuum annealing is in agreement with the (1 0 1) preferred crystalline orientation in Fig. 1b. Fig. 3 shows the absorption spectra of films before and after annealing at different annealing temperature. After annealing in air, the absorption is enhanced in the range of 350 nm to 450 nm with the increase of annealing temperature. From the plot of (aht)2 as a function of photon energy (ht) (Fig. S2), the bandgap (Eg) is deduced (Table 1). Eg decreases slightly with the increase
Fig. 2. Raman spectra of samples after annealing in air (a) and vacuum (b).
of annealing temperature, but sharply increases at temperature of 500 °C due to the formation of SnO2. The color of films shown in insets is changed from light yellow to dark yellow and then to white with the increase of the annealing temperature. When annealed in vacuum, the absorption in the range of short wavelength increases with the increase of annealing temperature, and reaches saturation, but Eg, deduced from Fig. S3, decreases slightly. Meanwhile, the color of films is changed from yellowish to dark yellow. The electrical properties of the films after annealing are studied by Hall effect measurement (Table 1). For the film annealed at 500 °C in air, n-type conductivity is obtained due to the formation of SnO2 phase. The exciting thing is that after annealing at moderate temperature, such as 300 °C or 400 °C, pure SnO films with ntype conduction are prepared, in which no evidence of metallic tin precipitates is observed, in contrast to Ref. [18]. The Hall mobility of ~5 cm2V 1s 1 is close to the reported values for n-SnO, 0.57 cm2V 1s 1 to 11 cm2V 1s 1 [8]. The formation mechanism of n-type SnO films during air annealing is shown in Fig. 4.
3
L. Pan et al. / Materials Letters 257 (2019) 126737
At 300–400 °C, O atoms diffuse into the gap of Sn-O-Sn layers to capture the Sn 5 s2 electrons without disturbing the layered structure, leading to the generation of Sn3+ state (Fig. S4) [19]. Another 5 s2 electron of Sn3+ becomes free electron. Once the concentration of free electrons exceeds that of holes, the film changes from p-type to n-type. However, at 500 °C, structural reconstruction is caused by intense oxidation, and SnO2 phase formed. When annealed in vacuum, p-type films are obtained at temperature of 200 °C to 500 °C with mobilities of 1.10–3.28 cm2V 1s 1, in accordance with the previous reports [8,15,20–22]. These studies laid the foundation for the subsequent construction of homogeneous junction and characteristic analysis, especially stability [23].
4. Conclusion In summary, SnO thin films have been synthesized by e-beam evaporation at room temperature, followed annealing in air and vacuum, respectively. With the increase of annealing temperature in air, the structure transforms from amorphous SnO into polycrystalline SnO and then into polycrystalline SnO2 phase. Interestingly, n-type SnO films are obtained after annealing at 300 °C and 400 °C, respectively. However, in case of annealing in vacuum, phase transition from amorphous SnO to polycrystalline SnO is found with the increase of annealing temperature, without the formation of SnO2. And the annealed films present p-type conductivity. So, this feasible and simple method for the fabrication of p- and n-type SnO films, which will contribute to expand their application field.
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Appendix A. Supplementary data
Fig. 3. Absorption spectra of SnO thin films before and after annealing in air (a) and vacuum (b). Insets show the photos of films.
Supplementary data to this article can be found online at https://doi.org/10.1016/j.matlet.2019.126737.
Table 1 Properties of films after annealing in air and vacuum, respectively. Conditions
Temperature ( )
Eg (eV)
p/n type
Resistivity (Xcm)
Carrier density (cm
as-deposited air
25 250 300 400 500 100 200 300 400 500
2.81 2.79 2.76 2.7 3.12 2.8 2.77 2.75 2.73 2.72
– – n n n – p p p p
– – 0.17 0.18 0.14 – 9.58 5.09 7.36 10.30
– – 5.63 1018 7.70 1018 4.10 1019 – 5.93 1017 9.16 1017 2.91 1017 1.85 1017
vacuum
3
)
Mobility (cm2v – – 6.63 4.53 1.08 – 1.10 1.34 2.92 3.28
1
s
1
)
4
L. Pan et al. / Materials Letters 257 (2019) 126737
Fig. 4. Formation mechanism of n-type SnO films during air annealing.
References [1] H. Luo, L. Liang, H. Cao, Carrier trapping anisotropy in ambipolar SnO thin-film transistors, Solid-State Electron. 129 (2017) 88–92. [2] A. Sharma, M. Varshney, K.D. Verma, Y. Kumar, R. Kumar, Structural and surface microstructure evolutions in SnO thin films under ion irradiation, Nucl. Instrum. Methods Phys. Res., Sect. B 308 (2013) 15–20. [3] M. Batzill, U. Diebold, The surface and materials science of tin oxide, Prog. Surf. Sci. 79 (2005) 47–154. [4] R. Barros, K.J. Saji, J.C. Waerenborgh, P. Barquinha, L. Pereira, E. Carlos, R. Martins, E. Fortunato, Role of structure and composition on the performances of p-type tin oxide thin-film transistors processed at low-temperatures, Nanomaterials 9 (2019) 320. [5] S.H. Kwon, H.J. Joo, H.I. Kwon, Effects of simultaneous ultraviolet and thermal treatments on physical and chemical properties of RF-sputtered p-type SnO thin-films, Ceram. Int. 44 (2018) 20883–20889. [6] N.F. Quackenbush, J.P. Allen, D.O. Scanlon, S. Sallis, J.A. Hewlett, A.S. Nandur, B. Chen, K.E. Smith, C. Weiland, D.A. Fischer, J.C. Woicik, B.E. White, G.W. Watson, L.F.J. Piper, Origin of the Bipolar Doping Behavior of SnO from X-ray Spectroscopy and Density Functional Theory, Chem. Mater. 25 (2013) 3114– 3123. [7] A.H.-T. Nguyen, M.-C. Nguyen, J. Choi, S. Han, J. Kim, R. Choi, Electrical performance enhancement of p-type tin oxide channel thin film transistor using aluminum doping, Thin Solid Films 641 (2017) 24–27. [8] H. Hayashi, S. Katayama, R. Huang, K. Kurushima, I. Tanaka, Selective fabrication of n- and p-type SnO films without doping, Phys. Status Solidi (RRL) – Rapid Res. Lett. 9 (2015) 192–196. [9] S.S. Lin, S.Y. Fan, Y.S. Tsai, Effects of annealing on wettability and physical properties of SnO thin films deposited at low RF power densities, Ceram. Int. 43 (2017) 1802–1808. [10] P.B. Barna, M. Adamik, Fundamental structure forming phenomena of polycrystalline films and the structure zone models, Thin Solid Films 317 (1998) 27–33. [11] G.H. Moh, Tin,, containing mineral systems. Part I: The Sn–Fe–S–O systems and mineral assemblages in ores, Chem. Erde. 33 (1974) 243–275.
[12] J.C. Platteeuw, G. Meyer, The system tin+oxygen, Trans. Faraday Soc. 52 (1955) 1066–1073. [13] H. Giefers, F. Porsch, G. Wortmann, Kinetics of the disproportionation of SnO, Solid State Ionics 176 (2005) 199–207. [14] J.H. Shin, J.Y. Song, Y.H. Kim, H.M. Park, Low temperature and self-catalytic growth of tetragonal SnO nanobranch, Mater. Lett. 64 (2010) 1120–1122. [15] L.Y. Liang, Z.M. Liu, H.T. Cao, X.Q. Pan, Microstructural, optical, and electrical properties of SnO thin films prepared on quartz via a two-step method, ACS Appl. Mater. Interfaces 2 (2010) 1060–1065. [16] L.Y. Liang, Z.M. Liu, H.T. Cao, Y.Y. Shi, X.L. Sun, Z. Yu, A.H. Chen, H.Z. Zhang, Y.Q. Fang, Improvement of phase stability and accurate determination of optical constants of SnO thin films by using Al2O3 capping layer, ACS Appl. Mater. Interfaces 2 (2010) 1565–1568. [17] Q. Liu, L. Liang, H. Cao, H. Luo, H. Zhang, J. Li, X. Li, F. Deng, Tunable crystallographic grain orientation and Raman fingerprints of polycrystalline SnO thin films, J. Mater. Chem. C 3 (2015) 1077–1081. [18] J.A. Caraveo-Frescas, P.K. Nayak, H.A. Al-Jawhari, D.B. Granato, U. Schwingenschlögl, H.N. Alshareeft, Record mobility in transparent p-type tin monoxide films and devices by phase engineering, Acs Nano 7 (6) (2013) 5160–5167. [19] X.Q. Pan, L. Fu, Tin oxide thin films grown on the (1012) sapphire substrate, J. Electroceram. 7 (2001) 35–46. [20] Y. Ogo, H. Hiramatsu, K. Nomura, H. Yanagi, T. Kamiya, M. Kimura, M. Hirano, H. Hosono, Tin monoxide as an s-orbital-based p-type oxide semiconductor: electronic structures and TFT application, Phys. Status Solidi A 206 (2009) 2187–2191. [21] Y. Ogo, H. Hiramatsu, K. Nomura, H. Yanagi, T. Kamiya, M. Hirano, H. Hosono, P-channel thin-film transistor using p-type oxide semiconductor, Appl. Phys. Lett. 93 (2008) 032113. [22] W. Guo, L. Fu, Y. Zhang, K. Zhang, L.Y. Liang, Z.M. Liu, H.T. Cao, X.Q. Pan, Microstructure, optical, and electrical properties of p-type SnO thin films, Appl. Phys. Lett. 96 (2010) 042113. [23] R. Sathyamoorthy, K.M. Abhirami, B. Gokul, S. Gautam, K.H. Chae, K. Asokan, Fabrication of p-n Junction Diode Using SnO/SnO2 Thin Films and Its Device Characteristics, Electron. Mater. Lett. 10 (2014) 743–747.