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In this paper, the stability, electronic structure, optical properties, and work function of GaN/g-C3N4 heterojunction are studied by using the first-principles plane wave ultra-soft pseudopotential method based on density functional theory. The electric field effect is also considered. The results show that the total energy for each of the three stacking modes changes little for using the two different dispersion correction methods, i.e. Tkatchenko-Scheffler and Grimme, and the total energy of mode II is the lowest, indicating that the structure of mode II is the most stable. The lattice mismatch ratio and lattice mismatch energy of GaN/g-C3N4 van der Waals heterojunction are very low, indicating that the heterojunction has good stability. The heterojunction retains the basic electronic properties of GaN and g-C3N4 to a great extent and can be used as a direct bandgap semiconductor material. It can be known from the work function and differential charge diagram that the charge on the heterojunction interface is transferred from GaN to g-C3N4, and a built-in electric field orientating g-C3N4 from GaN is formed at the interface. The built-in electric field of the heterojunction can effectively separate the photogenerated electron-hole pairs, which is conducive to improving the photocatalytic capability of the system. Further analysis shows that the applied electric field reduces the bandgap of GaN/g-C3N4 heterostructure to varying degrees. It makes it easier for electrons to transit from valence band to conduction band, which is conducive to improving the photocatalytic activity of the system. In addition, when the applied electric field is –0.6 V/Å and 0.5 V/Å separately, the semiconductor metal phase transition occurs in the heterojunction. When the applied electric field is higher than 0.3 V/Å and lower than –0.4 V/Å, in the energy band arrangement of the heterojunction there occurs the transition from type I to type II. This can better realize the separation of photogenerated electron-hole pairs and further improve the photocatalytic capactivity of the system. Therefore, the construction of heterojunction and application of external electric field proposed in this work constitute an effective means to improve the photocatalytic activity of the system.
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Keywords:
- electronic structure /
- optical properties /
- work function /
- external electric field
[1] Cao S W, Yu J G 2014 Phys. Chem. Lett. 5 2101Google Scholar
[2] Mao N, Gao X M, Zhang C, Shu C, Ma W Y, Wang F, Jiang J X 2019 Dalton. T. 48 14864Google Scholar
[3] Antil B, Kumar L, Ranjan R, Shenoy S, Tarafder K, Gopinath C S, Deka S 2021 ACS Appl. Energ. Mater. 4 3118Google Scholar
[4] Fu J W, Xu Q L, Low J X, Jiang C J, Yu J G 2019 A Appl. Catal. B-Environ. 243 556Google Scholar
[5] Song Y H, She X J, Yi J J, Mo Z, Liu L, Xu H, Li H M 2017 Phys. Status. Solidi. A 214 1600704Google Scholar
[6] Na S, Seo S, Lee H 2020 Catalysts 10 679Google Scholar
[7] Ali S M, Khan M A M, ALKhuraiji T S 2020 J. Mater. Sci-Mater. El. 31 14901Google Scholar
[8] Eisa M H 2019 Results Phys. 13 102330Google Scholar
[9] Tong T, Zhu B C, Jiang C J, Cheng B, Yu J G 2018 Appl. Surf. Sci. 433 1175Google Scholar
[10] Zhu B C, Zhang L Y, Cheng B, Yu Y, Yu J G 2021 Chin. J. Catal. 42 115Google Scholar
[11] Li H H, Wu Y, Li L, Gong Y Y, Niu L Y, Liu X J, Wang T, Sun C Q, Li C 2018 Appl. Surf. Sci. 457 735Google Scholar
[12] Liu X L, Ma R, Zhuang L, Hu B W, Chen J R, Liu X Y, Wang X K 2021 Crit. Rev. Env. Sci. Tec. 51 751Google Scholar
[13] Li S J, Li Y Y, Shao L X, Wang C D 2021 ChemistrySelect 6 181Google Scholar
[14] Ariyanti D, Mukhtar S, Ahmed N, Liu Z, Dong J, Gao W 2020 Int. J. Mod. Phys. B 34 2040067Google Scholar
[15] Li J Y, Liu B K, Han X L, Liu B B, Jiang J X, Liu S R, Zhang J T, Shi H Z 2021 Sep. Purif. Technol. 261 118306Google Scholar
[16] Wang G R, Jin Z L 2019 Chemistry Select 4 3602Google Scholar
[17] Xu Q L, Zhu B C, Jiang C J, Cheng B, Yu J G 2018 Solar RRL 2 1800006Google Scholar
[18] Zhang M, Liu X Z, Zeng X, Wang M F, Shen J Y, Liu R Y 2020 Chem. Phy. Lett. X 7 100049Google Scholar
[19] Ye C Y, Wang R, Wang H Y, Jiang F B 2020 BMC Chemistry 14 65Google Scholar
[20] Al-Zaqri N, Ahmed M A, Alsalme A, Alharthi F, Alsyahi A, Elmahgary M G, Galal A H 2021 J. Mater. Sci-Mater. El. 32 2601Google Scholar
[21] Ai C Z, Li J, Yang L, Wang Z P, Wang Z, Zeng Y M, Deng R, Lin S W, Wang C Z 2020 Chem. Sus. Chem. 13 4985Google Scholar
[22] Ma X G, Chen C, Hu J S, Zheng M K, Wang H H, Dong S J, Huang C Y, Chen X B 2019 J. Alloy. Compd. 788 1Google Scholar
[23] Xue Z, Zhang X Y, Qin J Q, Liu R P 2020 Appl. Surf. Sci. 510 145489Google Scholar
[24] Wu F, Zhang Z B, Cheng Z P, Zhou R Z, Lin Y L, Liu Y H, Wang Y Q, Cao X H, Liu M G, Liu Y H 2021 J. Radioanal. Nucl. Ch. 329 1125Google Scholar
[25] Lou P, Lee J Y 2020 ACS Appl. Mater. Inter. 12 14289Google Scholar
[26] Shu H B 2020 Mat. Sci. Eng. B-Adv. 261 114672Google Scholar
[27] Sivasamy R, Paredes-Gil K, Quero F 2022 Physica. E 135 114994Google Scholar
[28] Wang J, Shu H B, Liang P, Wang N, Cao D, Chen X S 2019 J. Phys. Chem. C 123 3861Google Scholar
[29] Li X R, Dai Y, Ma Y D, Han S H, Huang B B 2014 Phys. Chem. Chem. Phys. 16 4230Google Scholar
[30] Ye J X, Liu J W, An Y K 2020 Appl. Surf. Sci. 501 144262Google Scholar
[31] Bai K F, Cui Z, Li E L, Ding Y C, Zheng J S, Liu C, Zheng Y P 2020 Vacuum 180 109562Google Scholar
[32] Clark S J, Segall M D, Pickard C J, Hasnip P J, Probert M I J, Refson K, Payne M C 2005 Z. Krist. Cryst. Mater. 220 567Google Scholar
[33] Perdew J P, Burke K, Ernzerhof M 1996 Phys. Rev. Lett. 77 3865Google Scholar
[34] Tkatchenko A, Scheffler M 2009 Phys. Rev. Lett. 102 73005Google Scholar
[35] Chadi D J 1977 Phys. Rev. B 16 1746Google Scholar
[36] 危阳, 马新国, 祝林, 贺华, 黄楚云 2017 66 087101Google Scholar
Wei Y, Ma X G, Zhu L, He H, Huang C Y 2017 Acta. Phys. Sin. 66 087101Google Scholar
[37] Ma X G, Hu J S, He H, Dong S J, Huang C Y, Chen X B 2018 ACS Appl. Nano Mater. 1 5507Google Scholar
[38] Liu J J 2015 J. Phys. Chem. C 119 28417Google Scholar
[39] 郭丽娟, 胡吉松, 马新国, 项炬 2019 68 097101Google Scholar
Guo L J, Hu J S, Ma X G, Xiang J 2019 Acta. Phys. Sin. 68 097101Google Scholar
[40] Liao J M, Sa B S, Zhou J, Ahuja R, Sun Z 2014 J. Phys. Chem. C 118 17594Google Scholar
[41] Ivanov A S, Miller E, Boldyrev A I, Kameoka Y, Sato T, Tanaka K 2015 J. Phys. Chem. C 119 12008Google Scholar
[42] Yeoh K H, Yoon T L, Lim T L, Rusi, Ong D S 2019 Superlattice. Microst. 130 428Google Scholar
[43] 张丽丽, 夏桐, 刘桂安, 雷博程, 赵旭才, 王少霞, 黄以能 2019 68 017401Google Scholar
Zhang L L, Xia T, Liu G A, Lei B C, Zhao X C, Wang S X, Huang Y N 2019 Acta. Phys. Sin. 68 017401Google Scholar
[44] Pham T A, Ping Y, Galli G 2017 Nat. Mater. 16 401Google Scholar
[45] Liu Z R, Yu X, Li L L 2020 Chinese J. Catal. 41 534Google Scholar
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图 1 (a) GaN单胞俯视图; (b) g-C3N4单胞俯视图; (c) 3 × 3的单层GaN俯视图; (d) 2 × 2的单层g-C3N4俯视图; (e) GaN/g-C3N4异质结侧视图
Figure 1. Top views of primitive cells of monolayer GaN (a) and g-C3N4 (b); top views of (c) monolayer GaN with 3 × 3 lateral periodicity and (d) monolayer g-C3N4 with 2 × 2 lateral periodicity; (e) side view of GaN/g-C3N4 heterojunction.
图 2 (a) GaN/g-C3N4异质结的3种堆垛模式俯视图以及采用TS和Grimme色散修正方法获得的总能量; (b)几何优化后模式II的结合能与层间距的关系
Figure 2. (a) Top view of three stacking modes of GaN/g-C3N4 heterojunction and total energy obtained by TS and Grimme dispersion correction method; (b) the relation between the cohesive energies and interlayer spacing distance for stacking pattern II after geometric optimization.
图 3 (a) 单层GaN能带图; (b) 单层g-C3N4能带图; (c) GaN/g-C3N4异质结能带图; (d) GaN/g-C3N4异质结的总态密度及分态密度图; (e) 单层GaN、单层g-C3N4及异质结的吸收光谱图
Figure 3. Energy band diagram of (a) monolayer GaN, (b) monolayer g-C3N4 and (c) GaN/g-C3N4 heterojunction; (d) total density of states and partial density of states of GaN/g-C3N4 heterojunction; (e) absorption spectra of monolayer GaN, g-C3N4 and GaN/g-C3N4 heterojunction.
图 4 (a) 单层g-C3N4功函数; (b) 单层GaN功函数; (c) GaN/g-C3N4异质结功函数; (d) GaN/g-C3N4异质结的三维差分电荷密度图(绿色和紫色分别表示电荷耗尽和电荷积累)
Figure 4. Work function of (a) monolayer g-C3N4, (b) monolayer GaN and (c) GaN/g-C3N4 heterojunction; (d) three-dimensional differential charge density diagram of GaN/g-C3N4 heterojunction (green and purple represent charge depletion and charge accumulation, respectively).
图 5 在不同外加电场(–0.6—0.5 V/Å)下GaN/g-C3N4异质结的能带结构图, 能量零点设置为费米能级 (a) –0.6 V/Å; (b) –0.5 V/Å; (c) –0.4 V/Å; (d) –0.3 V/Å; (e) –0.2 V/Å; (f) –0.1 V/Å; (g) 0 V/Å; (h) 0.1 V/Å; (i) 0.2 V/Å; (j) 0.3 V/Å; (k) 0.4 V/Å; (l) 0.5 V/Å
Figure 5. Energy band structure of GaN/g-C3N4 heterojunction under different applied electric fields, with the energy zero set as the Fermi level: (a) –0.6 V/Å; (b) –0.5 V/Å; (c) –0.4 V/Å; (d) –0.3 V/Å; (e) –0.2 V/Å; (f) –0.1 V/Å; (g) 0 V/Å; (h) 0.1 V/Å; (i) 0.2 V/Å; (j) 0.3 V/Å; (k) 0.4 V/Å; (l) 0.5 V/Å.
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[1] Cao S W, Yu J G 2014 Phys. Chem. Lett. 5 2101Google Scholar
[2] Mao N, Gao X M, Zhang C, Shu C, Ma W Y, Wang F, Jiang J X 2019 Dalton. T. 48 14864Google Scholar
[3] Antil B, Kumar L, Ranjan R, Shenoy S, Tarafder K, Gopinath C S, Deka S 2021 ACS Appl. Energ. Mater. 4 3118Google Scholar
[4] Fu J W, Xu Q L, Low J X, Jiang C J, Yu J G 2019 A Appl. Catal. B-Environ. 243 556Google Scholar
[5] Song Y H, She X J, Yi J J, Mo Z, Liu L, Xu H, Li H M 2017 Phys. Status. Solidi. A 214 1600704Google Scholar
[6] Na S, Seo S, Lee H 2020 Catalysts 10 679Google Scholar
[7] Ali S M, Khan M A M, ALKhuraiji T S 2020 J. Mater. Sci-Mater. El. 31 14901Google Scholar
[8] Eisa M H 2019 Results Phys. 13 102330Google Scholar
[9] Tong T, Zhu B C, Jiang C J, Cheng B, Yu J G 2018 Appl. Surf. Sci. 433 1175Google Scholar
[10] Zhu B C, Zhang L Y, Cheng B, Yu Y, Yu J G 2021 Chin. J. Catal. 42 115Google Scholar
[11] Li H H, Wu Y, Li L, Gong Y Y, Niu L Y, Liu X J, Wang T, Sun C Q, Li C 2018 Appl. Surf. Sci. 457 735Google Scholar
[12] Liu X L, Ma R, Zhuang L, Hu B W, Chen J R, Liu X Y, Wang X K 2021 Crit. Rev. Env. Sci. Tec. 51 751Google Scholar
[13] Li S J, Li Y Y, Shao L X, Wang C D 2021 ChemistrySelect 6 181Google Scholar
[14] Ariyanti D, Mukhtar S, Ahmed N, Liu Z, Dong J, Gao W 2020 Int. J. Mod. Phys. B 34 2040067Google Scholar
[15] Li J Y, Liu B K, Han X L, Liu B B, Jiang J X, Liu S R, Zhang J T, Shi H Z 2021 Sep. Purif. Technol. 261 118306Google Scholar
[16] Wang G R, Jin Z L 2019 Chemistry Select 4 3602Google Scholar
[17] Xu Q L, Zhu B C, Jiang C J, Cheng B, Yu J G 2018 Solar RRL 2 1800006Google Scholar
[18] Zhang M, Liu X Z, Zeng X, Wang M F, Shen J Y, Liu R Y 2020 Chem. Phy. Lett. X 7 100049Google Scholar
[19] Ye C Y, Wang R, Wang H Y, Jiang F B 2020 BMC Chemistry 14 65Google Scholar
[20] Al-Zaqri N, Ahmed M A, Alsalme A, Alharthi F, Alsyahi A, Elmahgary M G, Galal A H 2021 J. Mater. Sci-Mater. El. 32 2601Google Scholar
[21] Ai C Z, Li J, Yang L, Wang Z P, Wang Z, Zeng Y M, Deng R, Lin S W, Wang C Z 2020 Chem. Sus. Chem. 13 4985Google Scholar
[22] Ma X G, Chen C, Hu J S, Zheng M K, Wang H H, Dong S J, Huang C Y, Chen X B 2019 J. Alloy. Compd. 788 1Google Scholar
[23] Xue Z, Zhang X Y, Qin J Q, Liu R P 2020 Appl. Surf. Sci. 510 145489Google Scholar
[24] Wu F, Zhang Z B, Cheng Z P, Zhou R Z, Lin Y L, Liu Y H, Wang Y Q, Cao X H, Liu M G, Liu Y H 2021 J. Radioanal. Nucl. Ch. 329 1125Google Scholar
[25] Lou P, Lee J Y 2020 ACS Appl. Mater. Inter. 12 14289Google Scholar
[26] Shu H B 2020 Mat. Sci. Eng. B-Adv. 261 114672Google Scholar
[27] Sivasamy R, Paredes-Gil K, Quero F 2022 Physica. E 135 114994Google Scholar
[28] Wang J, Shu H B, Liang P, Wang N, Cao D, Chen X S 2019 J. Phys. Chem. C 123 3861Google Scholar
[29] Li X R, Dai Y, Ma Y D, Han S H, Huang B B 2014 Phys. Chem. Chem. Phys. 16 4230Google Scholar
[30] Ye J X, Liu J W, An Y K 2020 Appl. Surf. Sci. 501 144262Google Scholar
[31] Bai K F, Cui Z, Li E L, Ding Y C, Zheng J S, Liu C, Zheng Y P 2020 Vacuum 180 109562Google Scholar
[32] Clark S J, Segall M D, Pickard C J, Hasnip P J, Probert M I J, Refson K, Payne M C 2005 Z. Krist. Cryst. Mater. 220 567Google Scholar
[33] Perdew J P, Burke K, Ernzerhof M 1996 Phys. Rev. Lett. 77 3865Google Scholar
[34] Tkatchenko A, Scheffler M 2009 Phys. Rev. Lett. 102 73005Google Scholar
[35] Chadi D J 1977 Phys. Rev. B 16 1746Google Scholar
[36] 危阳, 马新国, 祝林, 贺华, 黄楚云 2017 66 087101Google Scholar
Wei Y, Ma X G, Zhu L, He H, Huang C Y 2017 Acta. Phys. Sin. 66 087101Google Scholar
[37] Ma X G, Hu J S, He H, Dong S J, Huang C Y, Chen X B 2018 ACS Appl. Nano Mater. 1 5507Google Scholar
[38] Liu J J 2015 J. Phys. Chem. C 119 28417Google Scholar
[39] 郭丽娟, 胡吉松, 马新国, 项炬 2019 68 097101Google Scholar
Guo L J, Hu J S, Ma X G, Xiang J 2019 Acta. Phys. Sin. 68 097101Google Scholar
[40] Liao J M, Sa B S, Zhou J, Ahuja R, Sun Z 2014 J. Phys. Chem. C 118 17594Google Scholar
[41] Ivanov A S, Miller E, Boldyrev A I, Kameoka Y, Sato T, Tanaka K 2015 J. Phys. Chem. C 119 12008Google Scholar
[42] Yeoh K H, Yoon T L, Lim T L, Rusi, Ong D S 2019 Superlattice. Microst. 130 428Google Scholar
[43] 张丽丽, 夏桐, 刘桂安, 雷博程, 赵旭才, 王少霞, 黄以能 2019 68 017401Google Scholar
Zhang L L, Xia T, Liu G A, Lei B C, Zhao X C, Wang S X, Huang Y N 2019 Acta. Phys. Sin. 68 017401Google Scholar
[44] Pham T A, Ping Y, Galli G 2017 Nat. Mater. 16 401Google Scholar
[45] Liu Z R, Yu X, Li L L 2020 Chinese J. Catal. 41 534Google Scholar
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