Supporting Information InGaAs Nanomembrane/Si van der Waals Heterojunction Photodiodes with Broadband and High Photoresponsivity Doo-Seung Um, Youngsu Lee, Seongdong Lim, Jonghwa Park, Wen-Chun Yen, Yu-Lun Chueh, Hyung-jun Kim, and Hyunhyub Ko * School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan, ROC Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Korea E-mail: hyunhko@unist.ac.kr S-1
a) InAs In 0.53 Ga 0.47 As b) In 0.52 Al 0.48 As 20 nm 5 nm RMS = 0.55 nm 1 µm Figure S1. (a) Cross-sectional HRTEM image of the interface region between the InGaAs and InAlAs layers in the as-grown sample. (b) AFM image for a surface roughness analysis of the as-grown InGaAs sample. S-2
a) b) Counts (a.u.) 80.0k 60.0k 40.0k 20.0k In As Ga Si O Intensity (a.u.) 350 300 250 InAs GaAs Si AlAs InGaAs/Si 0.0 0 1 2 3 4 5 6 7 8 Etching time (min) InGaAs/InAlAs/InP 200 100 200 300 400 500 600 Raman shift (cm -1 ) Figure S2. (a) Nano-Auger depth profile of the InGaAs/Si heterojunction. (b) Raman shift of the InGaAs/Si heterojunction before (red line) and after (black line) transfer printing. S-3
a) b) E vac E vac χ Si ~4.05 ev SiO 2 χ InGaAs SiO 2 ~4.5 ev p-si ΔE c E c ~1.12 ev ~0.45 ev E c ΔE v n + -InGaAs E f ~0.08 ev E f ~0.75 ev E v E v Figure S3. Band diagrams of the n + -InGaAs/p-Si heterojunction device (a) after and (b) before the native oxide layer was removed. The native SiO2 layer was removed by HF treatment. S-4
a) b) c) d) Figure S4. (a, b) Bright and dark field images after heterointegration with imperfectly cleaned InGaAs layer and Si substrate. (c, d) Bright and dark field images after heterointegration with impeccably cleaned InGaAs layer and Si substrate. S-5
a) b) Native Si wafer 0 Anode Current (na)(a.u.) -5-10 -15 HF treated Si wafer -20-5 -4-3 -2-1 0 Anode Voltage (V) -2.0-5 -4-3 -2-1 0 Figure S5. (a) Dark currents and (b) photocurrents under white light illumination for the InGaAs/Si heterojunction photodetector. The red line is the dark current and photocurrent of the heterojunction device integrated with InGaAs and a native Si substrate without HF treatment. The blue line is the dark current and photocurrent of the heterojunction device integrated with InGaAs and a HF-treated Si substrate to remove the native SiO2 layer. Anode Current ( A)(a.u.) 0.0-0.5-1.0-1.5 HF treated Si wafer Anode Voltage (V) Native Si wafer S-6
Current Density (a.u.) 150 100 50 0 Bias Voltage On Under 750 nm 0 4.8 4.9 5.0 9.7 9.8 9.9 Time (s) Off 13.79 ms 18.38 ms Figure S6. Enlarged current response time at zero bias (0 V) and under 750 nm (48 µw) light illumination. S-7
EQE (%) 1800 1600 1400 1200 1000 800 600 400 200 400 600 800 1000 1200 Wavelength (nm) Figure S7. External quantum efficiency of the InGaAs/Si heterojunction photodiode. S-8
Table S1. Electrical and optical performances of Si-based heterojunction photodetectors for broadband photodetection. Type Process method Ideality factor Rectification Ratio Dark Current Photoresponsivity Spectral response Ref. InGaAs/Si (PN) epitaxial transfer 1.54 77300 @ ±3V 0.0744 ma/cm 2 @ - 3V 9.25 A/W @ 800 nm 400 nm~1250 nm This work InGaAs/Si (APD) wafer bonding 16 ma/cm 2 @ -5V 0.85 A/W @ 1310 nm (1) p-ingaas (MSM) wafer bonding 270nA @ 1V >1.05 A/W @ 1520-1630nm (2) InGaAs/Si (APD) wafer bonding 0.7 ma/cm 2 @ gain of 10 0.64 A/W @ 1310 nm (3) Strained Ge/Si (PIN) direct growth 1.1 ~1000 @ ±2V 0.22 ma/cm 2 @ -2V 0.87 A/W @ 1310 nm 650 nm~1605 nm (4) Ge/SiGe/Si (PIN) direct growth 21 ma/cm 2 @ -1V 0.18 A/W @ 850nm (5) Ge/Si (PN) direct growth 30 ma/cm 2 0.55 A/W @ -0.2 ~ - 5V 1000 nm~1750 nm (6) Graphene/Si (Schottky) CVD < 1 µa/cm 2 435 ma/w 400 nm~900 nm (7) MoS 2 /Si (PN) Exfoliation and transfer 1.83 5000 300 ma/w 450 nm~1050 nm (8) S-9
REFERENCES (1) Bitter, M.; Z. Pan,; Kristjansson, S.; Boman, L.; Gold, R.; Pauchard, A. InGaAs-on-Si Photodetectors for High-Sensitivity Detection. Proc. SPIE 5406, Infrared Technology and Applications XXX, 2004, 5406. 1-12 (2) Y. Cheng,; Ikku, Y.; Ichikawa, O.; Osada, T.; Hata, M.; Takenaka, M.; Takagi, S. Waveguide InGaAs MSM Photodetector for Chip-Scale Optical Interconnects on III- V CMOS Photonics Platform. Asia Communications and Photonics Conference, (Beijing, China) 2013, ATh3A.4. (3) Pauchard, A.; Mages, P.; Kang, Y.; Bitter, M.; Pan, Z.; Sengupta, D.; Hummel, S.; Lo, Y.-H.; Paul, K. Wafer-Bonded InGaAs/Silicon Avalanche Photodiodes. Proc. SPIE 4650, Photodetector Materials and Devices VII, (San Jose, CA, USA) 2002, 4650, 37-43. (4) Liu, J.; Michel, J.; Giziewicz, W.; Pan, D.; Wada, K.; Cannon, D. D.; Jongthammanurak, S.; Danielson, D. T.; Kimerling, L. C.; Chen, J. Highperformance, Tensile-Strained Ge p-i-n Photodetectors on a Si Platform. Appl. Phys. Lett. 2005, 87, 103501. (5) Loh, T.; Nguyen, H.; Murthy, R.; Yu, M.; Loh, W.; Lo, G.; Balasubramanian, N.; Kwong, D.; Wang, J.; Lee, S. Selective Epitaxial Germanium on Silicon-on-Insulator High Speed Photodetectors Using Low-Temperature Ultrathin Si0.8Ge0.2 Buffer. Appl. Phys. Lett. 2007, 91, 73503. (6) Colace, L.; Masini, G.; Assanto, G.; Luan, H.-C.; Wada, K.; Kimerling, L. Efficient High-Speed Near-Infrared Ge Photodetectors Integrated on Si substrates. Appl. Phys. Lett. 2000, 76, 1231-1233. (7) An, X.; Liu, F.; Jung, Y. J.; Kar, S. Tunable Graphene-Silicon Heterojunctions for Ultrasensitive Photodetection. Nano. Lett. 2013, 13, 909-916. S-10
(8) Wang, L.; Jie, J.; Shao, Z.; Zhang, Q.; Zhang, X.; Wang, Y.; Sun, Z.; Lee, S.-T. MoS2/Si Heterojunction with Vertically Standing Layered Structure for Ultrafast, High-Detectivity, Self-Driven Visible-Near Infrared Photodetectors. Adv. Funct. Mater. 2015, 25, 2910-2919. S-11