摘要(英) |
This thesis produced high-quality and single-crystal Ge quantum dots (QDs) using selectively oxidation of SiGe pillars, and demonstrated Ge-QD P-I-N near-infrared photodetectors with various sizes of Ge QD. The P-I-N photodetectors exhibit various near-infrared photoresponsivities by tuning different sizes of Ge-QD arrays integrated in the photodetectors. Under 2.5 mW illumination at 850, 980, 1310, and 1570 nm, the photodetectors exhibit the photo-current-to-dark-current ratio as high as 28, 15, 2.3, and 1.6, respectively. Under near-infrared illumination, the positive holes confined in the valance band offset between Ge QD and the Si substrate, establishing a built-in electric field (E-field), leading the transient response of the photodetectors as high as 440 MHz.
The other topic of this thesis focused the formation of near-infrared photodetectors with a 1-μm-thick Ge QD/Si heterojunction contained various number of Ge QD/Si stacks by using Ultra-High Vacuum Chemical Vapor Deposition (UHV-CVD), and investigated the photoresponsivity of the photodetectors affected by the number of Ge QD/Si stacks. The photo-current-to-dark-current ratio of the photodetectors is 4000 (0.45 mW), 2200 (0.45 mW), 52 (9.4 mW), and 4.2 (5.4 mW) under illumination at 850, 980, 1310, and 1570 nm, respectively. The open-circuit voltage increases with the number of heterojunction of Ge QD/Si, which indicates the increasing built-in E-field improves the photoresponsivity. |
參考文獻 |
[1] W. C. Dash et al., “Intrinsic optical absorption in single-crystal germanium and silicon at 77℃ and 300℃,” Physical Review, 99, 1151, (1955).
[2] J. Liu et al., “Ge-on-Si optoelectronics,” Thin Solid Films, 520, 3354, (2012).
[3] J. Michael, J. Liu and L. C. Kimerling, “High-performance Ge-on-Si photodetector,” Nature Photonics, 4, 527, (2010).
[4] F. K. LeGoues et al., “Anomalous strain relaxation in SiGe thin films and superlattices,” Physical Review Letters, 64, 1943, (1990).
[5] M. Oehem et al., “GeSn-on-Si normal incidence photodetectors with bandwidths more than 40 GHz,” Optics Express, 22, 839, (2014).
[6] S. B. Samavedam and E. A. Fitzgerald, “Novel dislocation structure and surface morphology effects in relaxed Ge/Si-Ge(graded)/Si structure,” Appl. Phys. Lett., 81, 3108, (1997).
[7] H. C. Luan et al., “High-quality Ge epilayers on Si with low threading-dislocation densities,” Appl. Phys. Lett., 79, 3431, (2001).
[8] Q. Li et al., “Selective growth of Ge on Si(100) through vias of SiO2 nanotemplate using solid source molecular beam epitaxy,” Appl. Phys. Lett., 83, 5032, (2003).
[9] J. L. Liu et al., “High-quality Ge films on Si substrates using Sb surfactant-mediated graded SiGe buffers,” Appl. Phys. Lett., 79, 3431, (2001).
[10] 郭銘浩, ““量身訂作”鍺量子點以應用於近紅外線光偵測元件之研製”,碩士論文,國立中央大學,民國 102 年
[11] A. K. Dutta and M. Saif Islam, “Novel broadband photodetector for optical communication,”Proc. of SPIE, 6014, 6014c, (2005).
[12] 施敏,(2002):半導體元件物理與製作技術。新竹市:交大。
[13] C. Y. Chien et al., “Size tunable Ge quantum dots for near-ultraviolet to near-infrared photosensing with high figures of merit,” Nanoscale, 6, 5303, (2014).
[14] B. C. Hsu, et al., “A high efficient 820 nm MOS Ge quantum dot photodetector,” IEEE Electron Device Letters, 24, 318, (2003).
[15] C. H. Lin and C. W. Liu, “MOS Si/Ge photodetectors,” Proc. of SPIE, 6368, 636806, (2006).
[16] H. T. Chang et al., “High quality multifold Ge/Si/Ge composite quantum dots for thermoelectric materials,” Appl. Phys. Lett., 102, 101902, (2013).
[17] D. Brunco et al., “Germanium MOSFET devices: Advances in materials understanding, process development, and electrical performance,” J.Electrochem. Soc, 155, H552, (2008).
[18] W. T. Lai et al., “SiGe quantum dots over Si pillars for visible to near-infrared broadband photodetection,” IEEE Photon. Technol. Lett., 25, 15, (2013).
[19] 吳梓豪, “生成鍺奈米量子點與鍺奈米殼於絕緣層基板上之應用研究”,碩士論文,國立中央大學,民國102年
[20] D.Ahn et al., “High performance, waveguide integrated Ge photodetectors,” Optics Express, 15, 3916, (2007).
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