| 학회 | 한국재료학회 |
| 학술대회 | 2017년 가을 (11/15 ~ 11/17, 경주 현대호텔) |
| 권호 | 23권 2호 |
| 발표분야 | 2. 2차원 반도체 합성 및 소자 응용(Synthesis and device applications of two-dimensional semiconductors) |
| 제목 | Surface and Interface Engineering of Two Dimensional Semiconductor via non-covalent approaches. |
| 초록 | As silicon complementary metal–oxide–semiconductor (CMOS) technology has scaled down to a few nanometers, the performance of CMOS transistors has faced fundamental limitations, such as short channel effects. Layered transition metal dichalcogenides (TMDs) have been considered as next generation semiconductor platforms because their atomically thin body allows enhanced electrostatic gate control and atomically scaled precision thickness control of the channel. However, integration of TMDs into the logic transistors has been limited due to 1) a lack of effective passivation techniques for defects in TMDs and 2) a lack of depositions method for gate dielectric on inert surfaces of TMDs. Here, the formation of an organic/inorganic van-der-Waals interface between a monolayer (ML) of titanyl phthalocyanine (TiOPc) and a ML of MoS2 is investigated as a defect passivation method. A strong negative charge transfer from MoS2 to TiOPc molecules is observed in scanning tunneling microscopy. As a result of a formation of the van-der-Waals interface, the ION/IOFF in back-gated MoS2 transistors increases by more than two orders of magnitude, while degradation in the photoluminescence signal is suppressed. The van-der-Waals interface can be expended to develop a seedling technique for deposition of ultrathin dielectric on the 2D materials. A ML TiOPc is employed as the seeding layer on WSe2, and a dielectric is deposited via atomic layer deposition (ALD). As a result, ALD pulses of trimethyl aluminum and H2O nucleate on the TiOPc, resulting in a uniform deposition of Al2O3 on the WSe2 surface. The field-effect transistor (FETs) formed using this process have a leakage current of 0.046 pA/µm2 at 1 V gate bias with 3.0 nm EOT, which is lower leakage current than prior reports. The n-branch of the FET yielded a subthreshold swing of 80 mV/decade without doping. |
| 저자 | Park1, Jun Hong2, Atresh Sanne3, Sara Fathipour4, Yuzheng Guo5, Matin Amani6, Ali Javey6, John Robertson7, Sanjay K. Banerjee3, Alan Seabaugh4, Andrew C. Kumme8 |
| 소속 | 1Center for Quantum Nanoscience, 2Institute for Basic Science, 3Univ. of Texas at Austin, 4Univ. of Notre Dame, 5Swansea Univ., 6Univ. of California at Berkeley, 7Univ. of Cambridge, 8Univ. of California |
| 키워드 | TMD; TiOPC; Organic; Charge Transfer; van-der-Waals; 2D materials |
