Lu Shan, Li Jialin, Shen Wanping, Wang Zichen, Ma Yecheng, Su Xinyu, Lu Yunhao, Li Linjun, Chen Zongping
State Key Laboratory of Silicon and Advanced Semiconductor Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China.
ACS Nano. 2023 Dec 12;17(23):24299-24307. doi: 10.1021/acsnano.3c09930. Epub 2023 Nov 22.
Titanium nitride as a typical transition metal nitride (TMN) has attracted increasing interest for its fascinating characteristics and widespread applications. However, the synthesis of two-dimensional (2D) atomically thin titanium nitride is still challenging which hinders its further research in electronic and optoelectronic fields. Here, 2D titanium nitride with a large area was prepared topochemical conversion of the titanate monolayer. The titanium nitride reveals a thickness-dependent metallic-to-semiconducting transition, where the atomically thin titanium nitride with a thickness of ∼1 nm exhibits an n-type semiconducting behavior and a highly sensitive photoresponse and displays photoswitchable resistance by repeated light irradiation. First-principles calculations confirm that the chemisorbed oxygen on the surface of the titanium nitride nanosheet depletes its electrons, while the light irradiation induced desorption of oxygen leads to increased electron doping and hence the conductance of titanium nitride. These results may allow the scalable synthesis of ultrathin TMNs and facilitate their fundamental physics research and next-generation optoelectronic applications.
氮化钛作为一种典型的过渡金属氮化物（TMN），因其迷人的特性和广泛的应用而受到越来越多的关注。然而，二维（2D）原子级超薄氮化钛的合成仍然具有挑战性，这阻碍了其在电子和光电子领域的进一步研究。在此，通过钛酸盐单层的拓扑化学转化制备了大面积的二维氮化钛。氮化钛呈现出厚度依赖的金属-半导体转变，其中厚度约为1 nm的原子级超薄氮化钛表现出n型半导体行为和高度灵敏的光响应，并通过反复光照显示出光开关电阻。第一性原理计算证实，氮化钛纳米片表面化学吸附的氧耗尽了其电子，而光照射诱导的氧脱附导致电子掺杂增加，从而提高了氮化钛的电导率。这些结果可能有助于超薄TMN的可扩展合成，并促进其基础物理研究和下一代光电子应用。
