| 학회 | 한국재료학회 |
| 학술대회 | 2021년 가을 (11/24 ~ 11/26, 경주 라한호텔) |
| 권호 | 27권 2호 |
| 발표분야 | G. 나노/박막 재료 분과 |
| 제목 | Bowing-Free Continuous Bandgap Modulation of Wafer-Scale WS2xSe2(1-x) Alloyed Monolayers Using Metal-Organic Chemical Vapor Deposition |
| 초록 | Transition metal dichalcogenides (TMDs) as a 2D semiconductor have recently attracted tremendous interest for emerging electronics and optoelectronics due to their exceptional properties and broad range bandgap energies. The composition-modulated bandgap engineering in a controlled manner is essential for realizing practical applications. Nevertheless, the large-scale and uniform growth of TMD-based alloyed monolayers remains a challenge. Here, we will present the wafer-scale homogeneous growth of monolayer WS2xSe2(1-x) alloyed films with precisely tunable bandgap using metal-organic chemical vapor deposition (MOCVD). First, WSe2 and WS2 monolayer films were uniformly grown over a 2-inch SiO2/Si substrate. In addition, the continuous bandgap tuning of tungsten dichalcogenide alloys was demonstrated by finely modulating the relative molar flow rate of sulfur and selenium precursors. The WS2xSe2(1-x) films showed a sequential shift of bandgap energies and lattice vibration modes upon varying the composition of alloys in photoluminescence (PL) and Raman spectra. The bandgap energies exhibit a nearly linear relationship with the chalcogen compositions, meaning a negligible bowing effect due to slight lattice mismatch, strain relaxation, and thermodynamic stability. Furthermore, we demonstrated that the multiply stacked films with various alloying compositions could have high and broad absorption spectra than monolayer and bi-layer films. The bandgap engineering of 2D semiconductors shown in this work would make an essential step for their practical uses in next-generation ultrathin electronics and optoelectronics. |
| 저자 | Hee Seong Kang, Chul-Ho Lee |
| 소속 | 고려대 |
| 키워드 | 2D semiconductor; Transition metal dichalcogenide; Bandgap engineering; MOCVD |
