[15p-A205-1~12] Recent progresses of device applications of low-dimensional materials

[15p-A205-10] Continuous Color-Tunable Light-Emitting Devices Based on Compositionally Graded Monolayer Transition Metal Dichalcogenide Alloys

〇Koh Ho¹, Hao Ou¹, Tomoyuki Yamada¹, Naoki Wasa², Hibiki Naito², Hiroto Ogura², Takahiko Endo², Zheng Liu³, Toshifumi Irisawa³, Kazuhiro Yanagi², Yusuke Nakanishi², Yanlin Gao⁴, Mina Maruyama⁴, Susumu Okada⁴, Keisuke Shinokita⁵, Kazunari Matsuda⁵, Yasumitsu Miyata², Taishi Takenobu¹ (1.Nagoya Univ., 2.Tokyo Metropolitan Univ., 3.AIST, 4.Tsukuba Univ., 5.Kyoto Univ.)

Keywords:Transition metal dichalcogenide, alloy, Light-emitting device

The diverse series of transition metal dichalcogenide (TMDC) materials has been employed in various optoelectronic applications, such as photodetectors and light-emitting diodes. Typically, the detection or emission range of optoelectronic devices is unique to the bandgap of the active material. Therefore, to improve the capability of these devices, extensive efforts have been devoted to tune the bandgap, such as gating and dielectric engineering. However, the controllability of these methods is severely limited (~0.1 eV). In contrast, alloying TMDCs is an effective approach that yields a composition-dependent bandgap and enables light emissions over a wide range. Here, we fabricated a color-tunable light-emitting device using compositionally graded TMDC alloys. The monolayer WS₂/WSe₂ alloy grown by chemical vapor deposition showed a spatial gradient in the light emission energy. We incorporated this alloy in an electrolyte-based light-emitting device structure that can tune the recombination zone. Thus, we successfully fabricated a continuous color-tunable light-emitting device by controlling the light-emitting positions.