Highlighted Publications

Nature Communications (2023)
Short-wave infrared cavity resonances in a single GeSn nanowire
Link to the paper
Strong second-harmonic generation in non-uniformly strained monolayer graphene
Link to the paper
High-precision wavelength tuning of GeSn nanobeam lasers via optically controlled strain engineering
Link to the paper
Link to the Inside Back Cover
Link to the eeNews Europe article
Nano Letters (2022)
Efficient avalanche photodiodes with a WSe2/MoS2 heterostructure via two-photon absorption
Pseudo-magnetic field-induced slow carrier dynamics in periodically strained graphene

Link to the Dong-A Ilbo (동아일보) news
Low-threshold optically pumped lasing in highly strained Ge nanowires

Link to the paper
Link to the Laser Focus World article

All Publications

Note 1: Asterisk (*) denotes corresponding author.
Note 2: Dagger (†) denotes equal contributions.


54. H. Joo†, J. Liu†, M. Chen†, D. Burt, B. Chomet, Y. Kim, X. Shi, K. Lu, L. Zhang, Z. Ikonic, Y. Sohn, C. Tan, C. Sirtori*, Y. Todorov*, and D. Nam*, ‌‌“Actively tunable lasing in GeSn nanomechanical oscillators," Nature NanotechnologyIn Revision

53. H. Joo†, Y. Kim†, M. Chen, D. Burt, L. Zhang, B. Son, M. Luo, Z. Ikonic, C. Lee, Y. Cho, C. Tan, and D. Nam*, ‌‌“All-around HfO2 stressor for tensile strain in GeSn-on-insulator nanobeam lasers,” Advanced Optical Materials, Accepted 

52. J. Tan†, X. Shi†, K. Lu, H. Joo, Y. Kim, M. Chen, L. Zhang, C. Tan, K. Lim, E. Quek, and D. Nam*, ‌‌“Enhanced second-harmonic generation in strained germanium-on-insulator microdisks for integrated quantum photonic technologies,” Optics Letters 48, 4269-4271 (2023) [PDF] 

51. Y. Kim†, S. Assali†, H. Joo, S. Koelling, M. Chen, L. Luo, X. Shi, D. Burt, Z. Ikonic, D. Nam*, and O. Moutanabbir*, ‌‌“Short-wave infrared cavity resonances in a single GeSn nanowire,” Nature Communications 14, 4393 (2023) [PDF]

50. Q. Chen, Y. Jung, H. Zhou, S. Wu, X. Gong, Y. Huang, K. Lee, L. Zhang, D. Nam, J. Liu, J. Luo, W. Fan, and C. Tan, ‌‌“GeSn/Ge multiquantum-well vertical-cavity surface-emitting p-i-n structures and diode emitters on a 200 mm Ge-on-insulator platform," ACS Photonics 10, 1716-1725 (2023) [PDF]

49. K. Lu†, M. Luo†, W. Gao, Q. Wang,  H. Sun*, and D. Nam*, ‌‌Strong second-harmonic generation in non-uniformly strained monolayer graphene,” Nature Communications 14, 2580 (2023) [PDF] 

48. M. Atalla†, Y. Kim†, S. Assali, D. Burt, D. Nam*, and O. Moutanabbir*, ‌‌“Extended-SWIR GeSn LEDs with reduced footprint and efficient operation power,” ACS Photonics 10, 1649-1653 (2023) [PDF]

47. Y. Kim†, H. Joo†, M. Chen, B. Son, D. Burt, X. Shi, L. Zhang, Z. Ikonic, C. Tan, and D. Nam*, ‌‌“High-precision wavelength tuning of GeSn nanobeam lasers via optically controlled strain engineering,” Advanced Science, 2207611 (2023) [PDF]
Selected for the Inside Back Cover & Covered by eeNews Europe, etc.

46. F. Wang, F. Hu, M. Dai, S. Zhu, F. Sun, R. Duan, C. Wang, J. Han, W. Deng, W. Chen, M. Ye, S. Han, B. Qiang, Y. Jin, Y. Chua, N. Chi, S. Yu, D. Nam, S. H. Chae, Z. Liu, and Q. Wang*, ‌‌“A two-dimensional mid-infrared optoelectronic retina enabling simultaneous perception and encoding,” Nature Communications 14, 1938 (2023) [PDF]

45. D. Burt†, L. Zhang†, Y. Jung, H. Joo, Y. Kim, M. Chen, B. Son, W. Fan, Z. Ikonic, C. Tan, and D. Nam*, ‌‌“Tensile strained direct bandgap GeSn microbridges enabled in GeSnOI substrates with residual tensile strain,” Optics Letters 48, 735-738 (2023) [PDF]


44. B. Son, Y. Wang, M. Luo, K. Lu, Y. Kim, H. Joo, Y. Yi, C. Wang, Q. Wang, S. Chae*, and D. Nam*, ‌‌“Efficient avalanche photodiodes with a WSe2/MoS2 heterostructure via two-photon absorption,” Nano Letters 22, 9516-9522 (2022) [PDF]

43. K. Lu, Y. Wang, M. Luo, B. Son, Y. Yu, and D. Nam*, ‌‌“Ultrafast light emission at telecom wavelengths from a wafer-scale monolayer graphene enabled by Fabry-Perot interferences,” Optics Letters 47, 4668-4671 (2022) [PDF]

42. Y. Wang†, D. Burt†, K. Lu, and D. Nam*, ‌‌“Second-harmonic generation in germanium-on-insulator from visible to telecom wavelengths,” Applied Physics Letters 120, 242105 (2022) [PDF]

41. D. Burt†, H. Joo†, Y. Kim†, Y. Jung, M. Chen, M. Luo, S. Parluhutan, D. Kang, S. Assali, L. Zhang, B. Son, C. Tan, O. Moutanabbir, Z. Ikonic, Y. Huang, and D. Nam*, ‌‌“Direct bandgap GeSn nanowires enabled with ultrahigh tension from harnessing intrinsic compressive strain,” Applied Physics Letters 120, 202103 (2022) [PDF]
Selected as an Editor's Pick

40. Y. Jung†, D. Burt†, L. Zhang, Y. Kim, H. Joo, M. Chen, S. Assali, O. Moutanabbir, C. Tan, and D. Nam*, ‌‌“Optically pumped low-threshold microdisk lasers in GeSn-on-insulator with reduced defect density,” Photonics Research 10, 06001332 (2022) [PDF]

39. M. Luo†, H. Sun†, Z. Qi, K. Lu, M. Chen, D. Kang, Y. Kim, D. Burt, X. Yu, C. Wang, Y. Kim, H. Wang, Q. Wang, and D. Nam*, ‌‌“Triaxially strained suspended graphene for large-area uniform pseudo-magnetic fields," Optics Letters 47, 2174-2177 (2022) [PDF] 

38. Y. Kim†, S. Assali†, D. Burt, Y. Jung, H. Joo, M. Chen, D. Kang, Z. Ikonic, O. Moutanabbir* and D. Nam*, “Enhanced GeSn microdisk lasers directly released on Si," Advanced Optical Materials 9, 2101213 (2022) [PDF]


37. H. Joo†, Y. Kim†, D. Burt, Y. Jung, L. Zhang, M. Chen, S. Parluhutan, D. Kang, C. Lee, S. Assali, O. Moutanabbir, Y. Cho, C. Tan, and D. Nam*, “1D photonic crystal direct bandgap GeSn-on-insulator laser,” Applied Physics Letters 119, 201101 (2021) [PDF]

36. X. Gao†, H. Sun†, Q. Wang, and D. Nam*, ‌‌“Heterostrain‐enabled dynamically tunable moiré superlattice in twisted bilayer graphene,” Scientific Reports 11, 21402 (2021) [PDF] 

35. B. Son, L. Zhang, Y. Jung, H. Zhou, D. Nam, C. Tan, “Systematic study on photoexcited carrier dynamics related to defects in GeSn films with low Sn content at room temperature,” Semiconductor Science and Technology 36, 125018 (2021) [PDF]  

34. D. Burt†, H. Joo†, Y. Jung, Y. Kim, M. Chen, Y. Huang, and D. Nam*, “Strain-relaxed GeSn-on-insulator (GeSnOI) microdisks,” Optics Express 28, 28959-28967 (2021) [PDF] 

33. D. Kang†, H. Sun†, M. Luo†, K. Lu, M. Chen, Y. Kim, Y. Jung, X. Gao, S. Parluhutan, J. Ge, S. Koh, D. Giovanni, T. Sum, Q. Wang, H. Li, and D. Nam*, “Pseudo-magnetic field-induced slow carrier dynamics in periodically strained graphene,” Nature Communications 12, 5087 (2021) [PDF] 
Covered by Optics & Photonics News (OPN)Dong-A Ilbo, etc.

32. C. Qimiao, W. Shaoteng, Z. Lin, Z. Hao, D. Burt, D. Nam, W. Fan, and C. Tan, “GeSn-on-insulator dual-waveband resonant-cavity-enhanced photodetectors at the 2 μm and 1.55 μm optical communication bands,” Optics Letters 46, 3809-3812 (2021) [PDF] 

31. J. Ge†, B. Ding†, S. Hou†, M. Luo, D. Nam, H. Duan*, H. Gao*, Y. Lam*, and H. Li*, “Rapid fabrication of complex nanostructures using room-temperature ultrasonic nanoimprinting,” Nature Communications 12, 3146 (2021) [PDF] 

30. O. Moutanabbir*, S. Assali, X. Gong, E. O'Reilly, C. Broderick, B. Marzban, J. Witzens, W. Du, S. Yu, A. Chelnokov, D. Buca, and D. Nam, “Monolithic infrared silicon photonics: The rise of (Si)GeSn semiconductors,” Applied Physics Letters 29, 118, 110502 (2021) [PDF]  

29. Y. Jung†, Y. Kim†, D. Burt, H. Joo, D. Kang, M. Luo, M. Chen, L. Zhang, C. Tan, and D. Nam*, “Biaxially strained germanium crossbeam with high-quality optical cavity for on-chip laser applications,” Optics Express 29, 14174-14181 (2021) [PDF] 

28. H. Sun*, P. Sengupta*, D. Nam*, and B. Yang*“Negative thermal Hall conductance in two-dimer Shastry-Sutherland model with π-flux Dirac triplon,” Physical Review B 103, L140404 (2021) [PDF] 

27. H. Sun, Z. Qi, Y. Kim, M. Luo, B. Yang, and D. Nam*, “Frequency-tunable terahertz graphene laser enabled by pseudomagnetic fields in strain-engineered graphene,” Optics Express 29, 1892-1902 (2021) [PDF] 
Covered by Optics & Photonics News 


26. A. Dubrovkin*, B. Qiang, T. Salim, D. Nam, N. Zheludev*, and Q.Wang*, “Resonant nanostructures for highly confined and ultra-sensitive surface phonon polaritons,” Nature Communications 11, 1863 (2020) [PDF]  

25. Z. Song, W. Fan*, C. Tan, Q. Wang, D. Nam, Z. Hua, and G. Sun, “Band structure of strained Ge1-xSnx alloy: a full-zone 30-band k·p model,” IEEE Journal of Quantum Electronics 56, 7100208 (2020) [PDF] 


24. H. Joo, M. Shin, H. Jung, H. Cha, D. Nam, and H. Kwon*, “Oxide thin-film transistor-based vertically stacked complementary inverter for logic and photo-sensor operations,” Materials 12, 3815 (2019) [PDF] 

23. Z. Song, W. Fan*, C. Tan, Q. Wang, D. Nam, Z. Hua, and G. Sun, “Band structure of Ge1-xSnx alloy: a full-zone 30-band k·p model,” New Journal of Physics 21, 073037 (2019) [PDF] 


22. Z. Qi, H. Sun, M. Luo, Y. Jung, and D. Nam*, "Strained germanium nanowire optoelectronic devices for photonic-integrated circuits," Journal of Physics: Condensed Matter 30(33), 334004 (2018) [PDF] 

21. S. Gupta*, D. Nam, J. Vuckovic and K. Saraswat, "Room temperature lasing unraveled by a strong resonance between gain and parasitic absorption in uniaxially strained germanium," Physical Review B 97(15), 155127 (2018) [PDF] 


20. S. Bao†, D. Kim†, C. Onwukaeme†, S. Gupta†, K. Saraswat, K. Lee, Y. Kim, D. Min, Y. Jung, H. Qiu, H. Wang, E. A. Fitzgerald, C. Tan* and D. Nam*, "Low-threshold optically pumped lasing in highly strained Ge nanowires," Nature Communications 8(1), 1845 (2017) [PDF] 
Covered by 
Laser Focus WorldChannel NewsAsiaetc. 

~2016 (Before Joining NTU)

19. D. Sukhdeo†, Y. Kim†, K. Saraswat, B. Dutt and D. Nam*, “Theoretical modeling for the interaction of tin alloying with n-type doping and tensile strain for GeSn lasers,” IEEE Electron Device Letters 37(10), 1307-1310 (2016) [PDF] 

18. J. Baek, B. Ki, D. Kim, C. Lee, D. Nam, Y. Cho, and J. Oh*, “Phosphorus implantation into in-situ doped Ge-on-Si for high light-emitting efficiency,” Optical Materials Express 6(9), 2939-2946 (2016) [PDF] 

17. D. Sukhdeo†, Y. Kim†, S. Gupta, K. Saraswat, B. Dutt and D. Nam*, “Anomalous threshold reduction from uniaxial strain for a low-threshold Ge laser,” Optical Communication 379, 32-35 (2016) [PDF] 

16. J. Petykiewicz†, D. Nam†, D. Sukhdeo, S. Gupta, S. Buckley, A. Piggott, J. Vučković* and K. Saraswat*, “Direct bandgap light emission from strained Ge nanowire coupled with high-Q optical cavities,” Nano Letters 16(4), 2168-2173 (2016) [PDF] 
Covered by 
Dong-A IlboDigital TimesNewsisAsia Today, etc.

15. D. Sukhdeo, S. Gupta, K. Saraswat, B. Dutt and D. Nam*, “Impact of minority carrier lifetime on the performance of strained Ge light sources,” Optical Communication 364, 233-237 (2016) [PDF] 

14. D. Sukhdeo, S. Gupta, K. Saraswat, B. Dutt and D. Nam*, “Ultimate limit of biaxial tensile strain and n-type doping for realizing an efficient low-threshold Ge laser,” Japanese Journal of Applied Physics 55, 024301 (2016) [PDF] 

13. D. Sukhdeo, J. Petykiewicz, S. Gupta, D. Kim, S. Woo, Y. Kim, J. Vučković, K. Saraswat and D. Nam*, “Ge microdisk with lithographically-tunable strain using CMOS-compatible process,” Optics Express 23(26), 33249-33254 (2015) [PDF] 

12. D. Sukhdeo, D. Nam*, J. Kang, M. Brongersma and K. Saraswat, “Bandgap-customizable germanium using lithographically determined biaxial tensile strain for silicon-compatible optoelectronics,” Optics Express 23(13), 16740-16749 (2015) [PDF] 

11. J. Nam*, F. Afshinmanesh, D. Nam, W. Jung, T. Kamins, M. Brongersma, and K. Saraswat, “Monolithic integration of germanium-on-insulator p-i-n photodetector on silicon,” Optics Express 23(12), 15816-15823 (2015) [PDF] 

10. J. Nam, S. Alkis, D. Nam, F. Afshinmanesh, J. Shim, J. Park, M. Brongersma, A. Okyay, T. Kamins and K. Saraswat*, “Lateral overgrowth for monolithic integration of germanium-on-insulator on silicon,” Journal of Crystal Growth 416, 21-27 (2015) [PDF] 

9. D. Nam*, J. Kang, M. Brongersma and K. Saraswat, “Observation of improved minority carrier lifetimes in high-quality Ge-on-insulator using time-resolved photoluminescence,” Optics Letters 39(21), 6205-6208 (2014) [PDF] 

8. D. Nam, D. Sukhdeo, S. Gupta, J. Kang, M. Brongersma and K. Saraswat, “Study of carrier statistics in uniaxially strained Ge for a low-threshold Ge laser,” IEEE Journal of Selected Topics in Quantum Electronics 20(4), 1500107 (2014) [PDF] 

7. D. Sukhdeo, D. Nam*, J. Kang, M. Brongersma and K. Saraswat, “Direct bandgap germanium-on-silicon inferred from 5.7% uniaxial tensile strain,” Photonics Research 2(3), A8-A13 (2014) [PDF] 
Selected as #1 most cited paper during 2014-2015 & 
Awarded a Highly Cited Paper Certificate in 2019

6. B. Dutt, H. Lin, D. Sukhdeo, B. Vulovic, S. Gupta, D. Nam, K. Saraswat, and J. Harris, “Theoretical analysis of GeSn alloys as a gain medium for a Si-compatible laser,” IEEE Journal of Selected Topics in Quantum Electronics 19(5), 1502706 (2013) [PDF] 

5. D. Nam, D. Sukhdeo, J. Kang, J. Petykiewicz, J. Lee, W. Jung, J. Vuckovic, M. Brongersma*, and K. Saraswat*, “Strain-induced pseudoheterostructure nanowires confining carriers at room temperature with nanoscale-tunable band profiles,” Nano Letters 13(7), 3118-3123 (2013) [PDF] 

4. B. Dutt*, D. Sukhdeo, D. Nam, B. Vulovic, Z. Yuan, and K. Saraswat, “Roadmap to an efficient germanium-on-silicon laser: strain vs. n-type doping,” IEEE Photonics Journal 4(5), 2002-2009 (2012) [PDF] 

3. W. Jung, J. Park, A. Nainani, D. Nam, and K. Saraswat, “Fluorine passivation of vacancy defects in bulk Ge metal-oxide-semiconductor field effect transistor application,” Applied Physics Letters 101(7), 072104 (2012) [PDF] 

2. D. Nam, D. Sukhdeo, S. Cheng, K. Huang, A. Roy, M. Brongersma, Y. Nishi, and K. Saraswat, “Electroluminescence from strained Ge membranes and implications for an efficient Si-compatible laser,” Applied Physics Letters 100(13), 131112 (2012) [PDF] 

1. D. Nam*, D. Sukhdeo, A. Roy, K. Balram, S. Cheng, K. Huang, Z. Yuan, M. Brongersma, Y. Nishi, D. Miller and K. Saraswat, “Strained germanium thin film membrane on silicon substrate for optoelectronics,” Optics Express 19(27), 25866-25872 (2011) [PDF] 


6. Non-Drafted Singapore Patent Application: “Biaxially strained crossbeam germanium laser structure,” D. Nam, D. Burt, Y. Jung, Y. Kim, H. Joo, Submitted on 16 Dec 2020

5. Non-Drafted Singapore Patent Application: “Graphene nanopillar structures for giant pseudo-magnetic fields,” D. Nam, D. Kang, M. Luo, H. Sun, X. Gao, K. Lu, Submitted on 15 Dec 2020

4. Non-Drafted Singapore Patent Application: “Triaxially strained graphene structure for large-area pseudo-magnetic field,” D. Nam, H. Sun, M. Luo, D. Burt, D. Kang, Submitted on 14 Dec 2020

3. Non-Drafted Singapore Patent Application, Application Number 10202012548S: “An electrically pumped strained GeSn laser structure,” D. Nam, D. Burt, Y. Jung, Y. Kim, H. Joo, Filed on 15 Dec 2020

2. Non-Drafted Singapore Patent Application, Application Number 10201806832X: “Highly strained germanium laser on a silicon platform,” D. Nam, C. Tan, Filed on 13 Aug 2018

1. US Patent No.0,372,455: “Crossed nanobeam structure for a low-threshold germanium laser,” D. Nam, J. Petykiewicz, D. Sukhdeo, S. Gupta, J. Vuckovic, K. Saraswat, Issued Sept. 9, 2015 [LINK]