2D Ma­te­ri­als

The focus of the 2D Ma­te­ri­als Re­search group is de­voted to the field of graphene and hBN process and tech­nol­ogy de­vel­op­ment. It deals with fun­da­men­tal in­ves­ti­ga­tions of graphene and hBN as well as the in­te­gra­tion of graphene based novel mod­ules into the sil­i­con tech­nol­ogy en­vi­ron­ment.

On one hand, it is of ut­most im­por­tance to un­der­stand and con­trol the mor­pho­log­i­cal, crys­tal­lo­graphic, chem­i­cal prop­er­ties and growth mech­a­nisms of 2D ma­te­ri­als. On the other hand, the de­vel­op­ments of graphene de­vices are also per­formed in con­di­tions re­sem­bling the Si-​based IC pro­duc­tion en­vi­ron­ment as closely as pos­si­ble. There­fore, we are aim­ing to bridge the gap be­tween cur­rent graphene re­search and state-​of-the-art 200 mm CMOS tech­nolo­gies. Suc­cess­ful col­lab­o­ra­tion be­tween the Ma­te­ri­als Re­search and Tech­nol­ogy de­part­ments as well as col­lab­o­ra­tions with na­tional and Eu­ro­pean part­ners are es­tab­lished in order to en­sure the out­comes of the 2D Ma­te­ri­als R&D.

Main tar­gets

  • re­search and de­vel­op­ment of 2D Ma­te­ri­als under CMOS com­pat­i­ble con­di­tions
  • iden­ti­fi­ca­tion and over­com­ing of the in­te­gra­tive chal­lenges of graphene tech­nol­ogy
  • de­sign, de­vel­op­ment and fab­ri­ca­tion of graphene based electro-​optic mod­u­la­tors

Re­search top­ics

  • quan­tum me­chan­i­cal mod­el­ling of the growth mech­a­nisms of graphene and hBN
  • sim­u­la­tions and mod­el­ing of de­vice per­for­mances
  • de­vel­op­ment of 200 mm CVD processes for high qual­ity graphene and hBN
  • con­trol and physics of substrate-​graphene in­ter­faces
  • fea­si­bil­ity study of hBN/graphene/hBN het­erostruc­tures
  • ad­vanced in-​situ and ex-​situ struc­tural and elec­tri­cal char­ac­ter­i­za­tions of 2D ma­te­ri­als
  • em­ploy­ment of new char­ac­ter­i­za­tion tools and meth­ods for 2D ma­te­ri­als analy­sis
  • in­ves­ti­ga­tions of graphene EA mod­u­la­tors and graphene-​semiconductor diodes
  • de­vel­op­ments of new ap­proaches for the fab­ri­ca­tion of graphene-​based de­vices
  • es­tab­lish­ment of 200 mm generic processes of graphene in CMOS pilot line

Re­search re­sults

Script list Pub­li­ca­tions

(1) Optimization of the Metal Deposition Process for the Accurate Estimation of Low Metal-Graphene Contact-Resistance
D. Capista, R. Lukose, F. Majnoon, M. Lisker, Ch. Wenger, M. Lukosius
Proc. 47th International ICT and Electronics Convention (MIPRO 2024), 1561 (2024)
DOI: 10.1109/MIPRO60963.2024.10569895, (2D-EPL)

(2) SWCNT-Si Photodetector with Voltage-Dependent Active Surface
D. Capista, L. Lozzi, A. Di Bartolomeo, F. Giubileo, N. Martucciello, M. Passacantando
Nano Express 5(1), 015004 (2024)
DOI: 10.1088/2632-959X/ad12d9
New works on Carbon Nanotubes-Silicon MIS heterostructures showed that the presence of thickness inhomogeneities in the insulating layer across the device can be exploited increase its functionalities. In this work, we report the fabrication and the characterization of a device consisting of a Single-Walled Carbon Nanotube (SWCNT) film onto an n-type silicon substrate where the nitride interlayer between the nanotubes and the silicon has been intentionally etched to obtain different thickness. Three different silicon nitride thicknesses allow the formation of three regions, inside the same device, each with different photocurrents and responsivity behaviors. We show that by selecting specific biases, the photoresponse of the regions can be switched on and off. This peculiar behavior allows the device to be used as a photodetector with a voltage dependent active surface. Scanning photo response imaging of the device surface, performed at different biases highlight this behavior.

(3) Advancing Graphene Integration in Si CMOS Technology: Challenges, Solutions, and Modulator Exploration
M. Lukosius, R. Lukose, P.K. Dubey, A.I. Raju, D. Capista, M. Lisker, A. Mai, Ch. Wenger
ECS Meeting Abstracts MA2024-02, 1455 (2024)
DOI: 10.1149/MA2024-02111455mtgabs, (2D-EPL)

(4) Graphene for Photonic Applications
M. Lukosius, R. Lukose, P.K. Dubey, A.I. Raju, M. Lisker, A. Mai, Ch. Wenger
Proc. 47th International ICT and Electronics Convention (MIPRO 2024), 1614 (2024)
DOI: 10.1109/MIPRO60963.2024.10569652, (2D-EPL)

(5) P-Type Schottky Contacts for Graphene Adjustable-Barriers Phototransistors
C. Strobel, C.A. Chavarin, M. Knaut, M. Albert, A. Heinzig, L. Gummadi, Ch. Wenger, T. Mikolajick
Nanomaterials 14(13), 1140 (2024)
DOI: 10.3390/nano14131140, (Graphen)
The graphene adjustable-barriers phototransistor is an attractive novel device for potential high speed and high responsivity dual-band photodetection. In this device graphene is embedded between the semiconductors silicon and germanium. Both n-type and p-type Schottky contacts between graphene and the semiconductors are required for this device. While n-type Schottky contacts are widely investigated, reports about p-type Schottky contacts between graphene and the two involved semiconductors are scarce. In this study, we demonstrate a p-type Schottky contact between graphene and p-germanium. A clear rectification with on-off ratios of close to 103 (± 5V) and a distinct photoresponse at telecommunication wavelengths in the infrared are achieved. Further, p-type silicon is transferred to or deposited on graphene and we also observe rectification and photoresponse in the visible range for some of these p-type Schottky junctions. These results are an important step towards a functional graphene adjustable-barriers phototransistor.

(6) High Gain Graphene Based Hot Electron Transistor with Record High Saturated Output Current Density
C. Strobel, C.A. Chavarin, M. Knaut, S. Völkel, M. Albert, A. Hiess, B. Max, Ch. Wenger, R. Kirchner, T. Mikolajick
Advanced Electronic Materials 10(2), 2300624 (2024)
DOI: 10.1002/aelm.202300624, (FFLEXCOM (D020))
Hot electron transistors (HETs) represent an exciting frontier in semiconductor technology, holding the promise of high-speed and high-frequency electronics. With the exploration of two-dimensional materials such as graphene and new device architectures, HETs are poised to revolutionize the landscape of modern electronics. This study highlights a novel HET structure with a record output current density of 800 A/cm² and a high current gain α, fabricated using a scalable fabrication approach. The HET structure comprises two-dimensional hexagonal boron nitride (hBN) and graphene layers wet transferred to a germanium substrate. The combination of these materials results in exceptional performance, particularly in terms of the highly saturated output current density. The scalable fabrication scheme used to produce the HET opens up opportunities for large-scale manufacturing. This breakthrough in HET technology holds promise for advanced electronic applications, offering high current capabilities in a practical and manufacturable device.

Dr. Min­dau­gas Luko­sius

IHP 
Im Tech­nolo­giepark 25
15236 Frank­furt (Oder)
Ger­many

Phone: +49 335 56 717
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