磁控溅射制备磷掺杂氧化锌薄膜及其性质的研究
摘要
氧化锌是一种宽带隙半导体(3.37eV),具有大的激子束缚能(60meV),在室温下容易获得强的激子发射,被认为是制备紫外发光和发光二极管的理想材料,在压电器件,紫外发光探测器,气敏传感器等方面都有十分重要的应用。因此,成为近年来继GaN之后宽带隙半导体研究领域的热点课题。
本论文针对氧化锌(ZnO)研究中的“磷掺杂p型ZnO的制备和性能”问题展开研究工作。采用磁控溅射方法,以高纯的Ar和O_2为溅射气体,ZnO:P_2O_5(2wt%)为靶材,在硅衬底上生长磷掺杂的ZnO薄膜,通过后期热处理提高了磷掺杂ZnO薄膜的结晶质量,改善了光学电学性质,并在750℃空气中快速热退火条件下获得磷掺杂的p型ZnO;系统研究了不同气体成分和不同退火温度对磷掺杂ZnO薄膜的结构、电学和光学性质的影响。本文还研究了退火对本征氧化锌薄膜的影响,通过氧化锌和磷掺杂氧化锌的对比,根据本文的实验结果并结合文献报道的内容对磷(P)掺杂形成p型氧化锌形成机制进行了探讨。
利用X-射线衍射、霍尔测量仪、Raman光谱及扫描电子显微镜对薄膜的性能进行了分析测试,并利用光致发光方法研究了薄膜的发光性质。
结果表明当Ar和O_2为流量比为1/0.05时,能观察到明显的紫外发光,可在快速热退火后得到磷掺杂p型ZnO薄膜,随着O_2含量增加,紫外发光峰逐渐消失,转变为n型;只有在750℃空气快速热退火后才能充分激活磷受主,得到了稳定的p型ZnO:P薄膜。随着退火温度的升高,氧化锌薄膜质量变好,当退火温度是900℃时,结晶质量最好,紫外发光和可见光之比最强。通过不掺杂氧化锌和磷掺杂氧化锌退火的对比得知,磷掺杂氧化锌中的磷取代晶格中锌的位置,在空气快速热退火中磷受主得到激活而表现为p型。
Zinc oxide is a wide band gap (3.37eV) semiconductor with a large exciton binding energy (60meV) and possesses strong exciton emission ability at room temperature. Zinc oxide is considered as an ideal material for UV light-emitting and diodes, widely utilized in piezoelectric parts, ultraviolet light detectors, gas sensors, and other aspects. Therefore, ZnO become a hot topic following the GaN in the wide band gap semiconductor field.
In this thesis, preparation of ZnO films and their doping into p-type with phosphorous were investigated. Phosphorus doped ZnO films were prepared on silicon substrate by magnetron sputtering by using high purity Ar and O_2 as the working gas and ZnO: P_2O_5(2wt%) as the target. The crystal quality, electrical and photoluminescence properties of phosphorus-doped ZnO films were improved by post-heat treatment. The phosphorus doped p-type ZnO films were successfully obtained by rapid annealing the phosphorus-doped ZnO films (RTA) at 750℃in air. The effects of annealing temperature and O_2/Ar ratio on structure and electrical and photoluminescence properties of phosphorus doped ZnO thin film were investigated and discussed in detail. This paper also studied the effects of annealing on the intrinsic ZnO films and compared the difference between the intrinsic ZnO and phosphorus doped zinc oxide in structure and properties. The formation mechanism of phosphorus (P) doped p-type zinc oxide was discussed according to the obtained and reported data.
Thin films were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), Hall measurements. The electronic and luminescence properties were tested by photoluminescence (PL).
Phosphorous-doped p-type ZnO films can be obtained by rapid annealing at 750 oC in air because the P dopants can be sufficiently preserved in the films and effectively activated. The optimal photoluminescence property was observed for the films deposited at the Ar/O_2 ratio of 1/0.05 and the near-band edge emission diminishes gradually with further increasing the Ar/O_2 ratio. With increasing annealing temperature the crystallinity and photoluminescence property improves and the optimal ones were obtained at 900 oC.
本论文针对氧化锌(ZnO)研究中的“磷掺杂p型ZnO的制备和性能”问题展开研究工作。采用磁控溅射方法,以高纯的Ar和O_2为溅射气体,ZnO:P_2O_5(2wt%)为靶材,在硅衬底上生长磷掺杂的ZnO薄膜,通过后期热处理提高了磷掺杂ZnO薄膜的结晶质量,改善了光学电学性质,并在750℃空气中快速热退火条件下获得磷掺杂的p型ZnO;系统研究了不同气体成分和不同退火温度对磷掺杂ZnO薄膜的结构、电学和光学性质的影响。本文还研究了退火对本征氧化锌薄膜的影响,通过氧化锌和磷掺杂氧化锌的对比,根据本文的实验结果并结合文献报道的内容对磷(P)掺杂形成p型氧化锌形成机制进行了探讨。
利用X-射线衍射、霍尔测量仪、Raman光谱及扫描电子显微镜对薄膜的性能进行了分析测试,并利用光致发光方法研究了薄膜的发光性质。
结果表明当Ar和O_2为流量比为1/0.05时,能观察到明显的紫外发光,可在快速热退火后得到磷掺杂p型ZnO薄膜,随着O_2含量增加,紫外发光峰逐渐消失,转变为n型;只有在750℃空气快速热退火后才能充分激活磷受主,得到了稳定的p型ZnO:P薄膜。随着退火温度的升高,氧化锌薄膜质量变好,当退火温度是900℃时,结晶质量最好,紫外发光和可见光之比最强。通过不掺杂氧化锌和磷掺杂氧化锌退火的对比得知,磷掺杂氧化锌中的磷取代晶格中锌的位置,在空气快速热退火中磷受主得到激活而表现为p型。
Zinc oxide is a wide band gap (3.37eV) semiconductor with a large exciton binding energy (60meV) and possesses strong exciton emission ability at room temperature. Zinc oxide is considered as an ideal material for UV light-emitting and diodes, widely utilized in piezoelectric parts, ultraviolet light detectors, gas sensors, and other aspects. Therefore, ZnO become a hot topic following the GaN in the wide band gap semiconductor field.
In this thesis, preparation of ZnO films and their doping into p-type with phosphorous were investigated. Phosphorus doped ZnO films were prepared on silicon substrate by magnetron sputtering by using high purity Ar and O_2 as the working gas and ZnO: P_2O_5(2wt%) as the target. The crystal quality, electrical and photoluminescence properties of phosphorus-doped ZnO films were improved by post-heat treatment. The phosphorus doped p-type ZnO films were successfully obtained by rapid annealing the phosphorus-doped ZnO films (RTA) at 750℃in air. The effects of annealing temperature and O_2/Ar ratio on structure and electrical and photoluminescence properties of phosphorus doped ZnO thin film were investigated and discussed in detail. This paper also studied the effects of annealing on the intrinsic ZnO films and compared the difference between the intrinsic ZnO and phosphorus doped zinc oxide in structure and properties. The formation mechanism of phosphorus (P) doped p-type zinc oxide was discussed according to the obtained and reported data.
Thin films were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), Hall measurements. The electronic and luminescence properties were tested by photoluminescence (PL).
Phosphorous-doped p-type ZnO films can be obtained by rapid annealing at 750 oC in air because the P dopants can be sufficiently preserved in the films and effectively activated. The optimal photoluminescence property was observed for the films deposited at the Ar/O_2 ratio of 1/0.05 and the near-band edge emission diminishes gradually with further increasing the Ar/O_2 ratio. With increasing annealing temperature the crystallinity and photoluminescence property improves and the optimal ones were obtained at 900 oC.
引文
1 ABMA Ashrafi, A Ueta, A Avramescu, et al. Growth and characterization of hypothetical zinc-blende ZnO films on GaAs (001) substrates with ZnS buffer layers. Applied Physics Letters. 2000, 76: 550
2 F Decremps, J Pellicer-Porres, F Datchi, et al. Trapping of cubic ZnO nanocrystallites at ambient conditions. Applied Physics Letters. 2002, 81: 4820
3 C Klingshirn. ZnO: From basics towards applications. physica status solidi (b). 2007, 244(9): 3027-3073
4 T Matsuoka, N Yoshimoto, T Sasaki, et al. Wide-gap semiconductor InGaN and InGaAlN grown by MOVPE. Journal of Electronic Materials. 1992, 21(2): 157-163
5 F Hamdani, A Botchkarev, W Kim, et al. Optical properties of GaN grown on ZnO by reactive molecular beam epitaxy. Applied Physics Letters. 1997, 70: 467
6 F Hamdani, M Yeadon, DJ Smith, et al. Microstructure and optical properties of epitaxial GaN on ZnO (0001) grown by reactive molecular beam epitaxy. Journal of Applied Physics. 1998, 83: 983
7 PF Yang, HC Wen, SR Jian, et al. Characteristics of ZnO thin films prepared by radio frequency magnetron sputtering. Microelectronics Reliability. 2008, 48(3): 389-394
8 SA Studenikin, N Golego, M Cocivera. Fabrication of green and orange photoluminescent, undoped ZnO films using spray pyrolysis. Journal of Applied Physics. 1998, 84: 2287
9 S Goldsmith. Filtered vacuum arc deposition of undoped and doped ZnO thin films: Electrical, optical, and structural properties. Surface and Coatings Technology. 2006, 201(7): 3993-3999
10 J Zhao, L Hu, W Wang, et al. Effects of growth atmosphere and homo-buffer layer on properties of ZnO films prepared on Si (111) by PLD. Vacuum. 2008, 82(6): 664-667
11 H Li, J Wang, H Liu, et al. Sol-gel preparation of transparent zinc oxide films with highly preferential crystal orientation. Vacuum. 2004, 77(1): 57-62
12 HW Liang, YM Lu, DZ Shen, et al. Investigation of growth mode in ZnO thin films prepared at different temperature by plasma-molecular beam epitaxy. Journal of Crystal Growth. 2005, 278(1-4): 305-310
13 LX Shao, J Zhang. A simple preparation technique of ZnO thin film with highcrystallinity and UV luminescence intensity. Journal of Physics and Chemistry of Solids. 2008, 69(2-3): 531-534
14 WI Park, YH Jun, SW Jung, et al. Excitonic emissions observed in ZnO single crystal nanorods. Applied Physics Letters. 2003, 82: 964
15 V Craciun, J Elders, JGE Gardeniers, et al. Growth of ZnO thin films on GaAs by pulsed laser deposition. Thin Solid Films. 1995, 259(1): 1-4
16 HW Kim, NH Kim. Structural studies of room-temperature RF magnetron sputtered ZnO films under different RF powered conditions. Materials Science and Engineering B. 2003, 103(3): 297-302
17 T Minami, S Ida, T Miyata, et al. Transparent conducting ZnO thin films deposited by vacuum arc plasma evaporation. Thin Solid Films. 2003, 445(2): 268-273
18 SF Chichibu, T Sota, G Cantwell, et al. Polarized photoreflectance spectra of excitonic polaritons in a ZnO single crystal. Journal of Applied Physics. 2003, 93: 756
19 YW Heo, SJ Park, K Ip, et al. Transport properties of phosphorus-doped ZnO thin films. Applied Physics Letters. 2003, 83: 1128
20 T Yamamoto, H Katayama-Yoshida. Solution using a codoping method to unipolarity for the fabrication of p-type ZnO. Japanese Journal of Applied Physics Part 2 Letters. 1999, 38: 166-169
21 JG Lu, LP Zhu, ZZ Ye, et al. p-type ZnO films by codoping of nitrogen and aluminum and ZnO-based pn homojunctions. Journal of Crystal Growth. 2005, 283(3-4): 413-417
22 CG Van de Walle. Hydrogen as a cause of doping in zinc oxide. Physical review letters. 2000, 85(5): 1012-1015
23 SB Zhang, SH Wei, A Zunger. Intrinsic n-type versus p-type doping asymmetry and the defect physics of ZnO. Physical Review B. 2001, 63(7): 75205
24 DC Look, JW Hemsky, JR Sizelove. Residual native shallow donor in ZnO. Physical Review Letters. 1999, 82(12): 2552-2555
25 A Janotti, CG Van de Walle. Oxygen vacancies in ZnO. Applied Physics Letters. 2005, 87: 122102
26 DM Hofmann, A Hofstaetter, F Leiter, et al. Hydrogen: A relevant shallow donor in zinc oxide. Physical Review Letters. 2002, 88(4): 45504
27 CH Seager, SM Myers. Quantitative comparisons of dissolved hydrogen density and the electrical and optical properties of ZnO. Journal of Applied Physics. 2003, 94: 2888
28 AF Kohan, G Ceder, D Morgan, et al. First-principles study of native point defects in ZnO. Physical Review B. 2000, 61(22): 15019-15027
29 CH Park, SB Zhang, SH Wei. Origin of p-type doping difficulty in ZnO: The impurity perspective. Physical Review B. 2002, 66(7): 73202
30 K Minegishi, Y Koiwai, Y Kikuchi, et al. Growth of p-type zinc oxide films by chemical vapor deposition. Japanese Journal of Applied Physics. 1997, 36(11A): L1453-L1455
31 DC Look, DC Reynolds, CW Litton, et al. Characterization of homoepitaxial p-type ZnO grown by molecular beam epitaxy. Applied Physics Letters. 2002, 81: 1830
32 Y Yan, SB Zhang, ST Pantelides. Control of doping by impurity chemical potentials: Predictions for p-type ZnO. Physical Review Letters. 2001, 86(25): 5723-5726
33 X Li, Y Yan, TA Gessert, et al. Chemical vapor deposition-formed p-type ZnO thin films. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films. 2003, 21: 1342
34 A Zunger. Practical doping principles. Applied Physics Letters. 2003, 83: 57
35 T Aoki, Y Hatanaka, DC Look. ZnO diode fabricated by excimer-laser doping. Applied Physics Letters. 2000, 76: 3257
36 KK Kim, HS Kim, DK Hwang, et al. Realization of p-type ZnO thin films via phosphorus doping and thermal activation of the dopant. Applied Physics Letters. 2003, 83: 63
37 YR Ryu, TS Lee, HW White. Properties of arsenic-doped p-type ZnO grown by hybrid beam deposition. Applied Physics Letters. 2003, 83: 87
38 YR Ryu, TS Lee, JH Leem, et al. Fabrication of homostructural ZnO p¨Cn junctions and ohmic contacts to arsenic-doped p-type ZnO. Applied Physics Letters. 2003, 83: 4032
39 S Limpijumnong, SB Zhang, SH Wei, et al. Doping by large-size-mismatched impurities: the microscopic origin of arsenic-or antimony-doped p-type zinc oxide. Physical Review Letters. 2004, 92(15): 155504
40 T Yamamoto, H Katayama-Yoshida. Unipolarity of ZnO with a wide-band gap and its solution using codoping method. Journal of Crystal Growth. 2000, 214(1): 552-555
41 M Joseph, H Tabata, H Saeki, et al. Fabrication of the low-resistive p-type ZnO by codoping method. Physica B: Condensed Matter. 2001, 302: 140-148
42 AV Singh, RM Mehra, A Wakahara, et al. p-type conduction in codoped ZnO thin films. Journal of Applied Physics. 2003, 93: 396
43 S Swann. Magnetron sputtering. Physics in Technology. 1988, 19: 67-75
44 RD Arnell, PJ Kelly. Recent advances in magnetron sputtering. Surface and Coatings Technology. 1999, 112(1-3): 170-176
45 JW Lyding, HO Marcy, TJ Marks, et al. Computer automated charge transport measurement system. IEEE Transactions on Instrumentation and Measurement. 1988, 37(1): 76-80
46 Z Chen. Characterization, functionalization, and assembly of silicon based nanowires and their applications in FETs and sensor devices. City University of Hong Kong. 2007:
47 PJ Kelly, RD Arnell. Magnetron sputtering: a review of recent developments and applications. Vacuum. 2000, 56(3): 159-172
48 B Yao, DZ Shen, ZZ Zhang, et al. Effects of nitrogen doping and illumination on lattice constants and conductivity behavior of zinc oxide grown by magnetron sputtering. Journal of Applied Physics. 2006, 99: 123510
49 V Vaithianathan, BT Lee, SS Kim. Pulsed-laser-deposited p-type ZnO films with phosphorus doping. Journal of Applied Physics. 2005, 98: 043519
50 JH Yang, HS Kim, JH Lim, et al. The Effect of Ar¨M O Sputtering Gas on the Phosphorus-Doped p-Type ZnO Thin Films. Journal of the Electrochemical Society. 2006, 153: G242
51 NY Garces, L Wang, L Bai, et al. Role of copper in the green luminescence from ZnO crystals. Applied Physics Letters. 2002, 81: 622
52 WJ Lee, J Kang, KJ Chang. Electronic structure of phosphorus dopants in ZnO. Physica B: Condensed Matter. 2006, 376: 699-702
2 F Decremps, J Pellicer-Porres, F Datchi, et al. Trapping of cubic ZnO nanocrystallites at ambient conditions. Applied Physics Letters. 2002, 81: 4820
3 C Klingshirn. ZnO: From basics towards applications. physica status solidi (b). 2007, 244(9): 3027-3073
4 T Matsuoka, N Yoshimoto, T Sasaki, et al. Wide-gap semiconductor InGaN and InGaAlN grown by MOVPE. Journal of Electronic Materials. 1992, 21(2): 157-163
5 F Hamdani, A Botchkarev, W Kim, et al. Optical properties of GaN grown on ZnO by reactive molecular beam epitaxy. Applied Physics Letters. 1997, 70: 467
6 F Hamdani, M Yeadon, DJ Smith, et al. Microstructure and optical properties of epitaxial GaN on ZnO (0001) grown by reactive molecular beam epitaxy. Journal of Applied Physics. 1998, 83: 983
7 PF Yang, HC Wen, SR Jian, et al. Characteristics of ZnO thin films prepared by radio frequency magnetron sputtering. Microelectronics Reliability. 2008, 48(3): 389-394
8 SA Studenikin, N Golego, M Cocivera. Fabrication of green and orange photoluminescent, undoped ZnO films using spray pyrolysis. Journal of Applied Physics. 1998, 84: 2287
9 S Goldsmith. Filtered vacuum arc deposition of undoped and doped ZnO thin films: Electrical, optical, and structural properties. Surface and Coatings Technology. 2006, 201(7): 3993-3999
10 J Zhao, L Hu, W Wang, et al. Effects of growth atmosphere and homo-buffer layer on properties of ZnO films prepared on Si (111) by PLD. Vacuum. 2008, 82(6): 664-667
11 H Li, J Wang, H Liu, et al. Sol-gel preparation of transparent zinc oxide films with highly preferential crystal orientation. Vacuum. 2004, 77(1): 57-62
12 HW Liang, YM Lu, DZ Shen, et al. Investigation of growth mode in ZnO thin films prepared at different temperature by plasma-molecular beam epitaxy. Journal of Crystal Growth. 2005, 278(1-4): 305-310
13 LX Shao, J Zhang. A simple preparation technique of ZnO thin film with highcrystallinity and UV luminescence intensity. Journal of Physics and Chemistry of Solids. 2008, 69(2-3): 531-534
14 WI Park, YH Jun, SW Jung, et al. Excitonic emissions observed in ZnO single crystal nanorods. Applied Physics Letters. 2003, 82: 964
15 V Craciun, J Elders, JGE Gardeniers, et al. Growth of ZnO thin films on GaAs by pulsed laser deposition. Thin Solid Films. 1995, 259(1): 1-4
16 HW Kim, NH Kim. Structural studies of room-temperature RF magnetron sputtered ZnO films under different RF powered conditions. Materials Science and Engineering B. 2003, 103(3): 297-302
17 T Minami, S Ida, T Miyata, et al. Transparent conducting ZnO thin films deposited by vacuum arc plasma evaporation. Thin Solid Films. 2003, 445(2): 268-273
18 SF Chichibu, T Sota, G Cantwell, et al. Polarized photoreflectance spectra of excitonic polaritons in a ZnO single crystal. Journal of Applied Physics. 2003, 93: 756
19 YW Heo, SJ Park, K Ip, et al. Transport properties of phosphorus-doped ZnO thin films. Applied Physics Letters. 2003, 83: 1128
20 T Yamamoto, H Katayama-Yoshida. Solution using a codoping method to unipolarity for the fabrication of p-type ZnO. Japanese Journal of Applied Physics Part 2 Letters. 1999, 38: 166-169
21 JG Lu, LP Zhu, ZZ Ye, et al. p-type ZnO films by codoping of nitrogen and aluminum and ZnO-based pn homojunctions. Journal of Crystal Growth. 2005, 283(3-4): 413-417
22 CG Van de Walle. Hydrogen as a cause of doping in zinc oxide. Physical review letters. 2000, 85(5): 1012-1015
23 SB Zhang, SH Wei, A Zunger. Intrinsic n-type versus p-type doping asymmetry and the defect physics of ZnO. Physical Review B. 2001, 63(7): 75205
24 DC Look, JW Hemsky, JR Sizelove. Residual native shallow donor in ZnO. Physical Review Letters. 1999, 82(12): 2552-2555
25 A Janotti, CG Van de Walle. Oxygen vacancies in ZnO. Applied Physics Letters. 2005, 87: 122102
26 DM Hofmann, A Hofstaetter, F Leiter, et al. Hydrogen: A relevant shallow donor in zinc oxide. Physical Review Letters. 2002, 88(4): 45504
27 CH Seager, SM Myers. Quantitative comparisons of dissolved hydrogen density and the electrical and optical properties of ZnO. Journal of Applied Physics. 2003, 94: 2888
28 AF Kohan, G Ceder, D Morgan, et al. First-principles study of native point defects in ZnO. Physical Review B. 2000, 61(22): 15019-15027
29 CH Park, SB Zhang, SH Wei. Origin of p-type doping difficulty in ZnO: The impurity perspective. Physical Review B. 2002, 66(7): 73202
30 K Minegishi, Y Koiwai, Y Kikuchi, et al. Growth of p-type zinc oxide films by chemical vapor deposition. Japanese Journal of Applied Physics. 1997, 36(11A): L1453-L1455
31 DC Look, DC Reynolds, CW Litton, et al. Characterization of homoepitaxial p-type ZnO grown by molecular beam epitaxy. Applied Physics Letters. 2002, 81: 1830
32 Y Yan, SB Zhang, ST Pantelides. Control of doping by impurity chemical potentials: Predictions for p-type ZnO. Physical Review Letters. 2001, 86(25): 5723-5726
33 X Li, Y Yan, TA Gessert, et al. Chemical vapor deposition-formed p-type ZnO thin films. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films. 2003, 21: 1342
34 A Zunger. Practical doping principles. Applied Physics Letters. 2003, 83: 57
35 T Aoki, Y Hatanaka, DC Look. ZnO diode fabricated by excimer-laser doping. Applied Physics Letters. 2000, 76: 3257
36 KK Kim, HS Kim, DK Hwang, et al. Realization of p-type ZnO thin films via phosphorus doping and thermal activation of the dopant. Applied Physics Letters. 2003, 83: 63
37 YR Ryu, TS Lee, HW White. Properties of arsenic-doped p-type ZnO grown by hybrid beam deposition. Applied Physics Letters. 2003, 83: 87
38 YR Ryu, TS Lee, JH Leem, et al. Fabrication of homostructural ZnO p¨Cn junctions and ohmic contacts to arsenic-doped p-type ZnO. Applied Physics Letters. 2003, 83: 4032
39 S Limpijumnong, SB Zhang, SH Wei, et al. Doping by large-size-mismatched impurities: the microscopic origin of arsenic-or antimony-doped p-type zinc oxide. Physical Review Letters. 2004, 92(15): 155504
40 T Yamamoto, H Katayama-Yoshida. Unipolarity of ZnO with a wide-band gap and its solution using codoping method. Journal of Crystal Growth. 2000, 214(1): 552-555
41 M Joseph, H Tabata, H Saeki, et al. Fabrication of the low-resistive p-type ZnO by codoping method. Physica B: Condensed Matter. 2001, 302: 140-148
42 AV Singh, RM Mehra, A Wakahara, et al. p-type conduction in codoped ZnO thin films. Journal of Applied Physics. 2003, 93: 396
43 S Swann. Magnetron sputtering. Physics in Technology. 1988, 19: 67-75
44 RD Arnell, PJ Kelly. Recent advances in magnetron sputtering. Surface and Coatings Technology. 1999, 112(1-3): 170-176
45 JW Lyding, HO Marcy, TJ Marks, et al. Computer automated charge transport measurement system. IEEE Transactions on Instrumentation and Measurement. 1988, 37(1): 76-80
46 Z Chen. Characterization, functionalization, and assembly of silicon based nanowires and their applications in FETs and sensor devices. City University of Hong Kong. 2007:
47 PJ Kelly, RD Arnell. Magnetron sputtering: a review of recent developments and applications. Vacuum. 2000, 56(3): 159-172
48 B Yao, DZ Shen, ZZ Zhang, et al. Effects of nitrogen doping and illumination on lattice constants and conductivity behavior of zinc oxide grown by magnetron sputtering. Journal of Applied Physics. 2006, 99: 123510
49 V Vaithianathan, BT Lee, SS Kim. Pulsed-laser-deposited p-type ZnO films with phosphorus doping. Journal of Applied Physics. 2005, 98: 043519
50 JH Yang, HS Kim, JH Lim, et al. The Effect of Ar¨M O Sputtering Gas on the Phosphorus-Doped p-Type ZnO Thin Films. Journal of the Electrochemical Society. 2006, 153: G242
51 NY Garces, L Wang, L Bai, et al. Role of copper in the green luminescence from ZnO crystals. Applied Physics Letters. 2002, 81: 622
52 WJ Lee, J Kang, KJ Chang. Electronic structure of phosphorus dopants in ZnO. Physica B: Condensed Matter. 2006, 376: 699-702