Making Large‐Area Titanium Disulfide Films at Reduced Temperature by Balancing the Kinetics of Sulfurization and Roughening

Abstract

The synthesis of large‐area TiS2 thin films is reported at temperatures as low as 500 °C using a scalable two‐step method of metal film deposition followed by sulfurization in an H2S gas furnace. It is demonstrated that the lowest‐achievable sulfurization temperature depends strongly on the oxygen background during sulfurization. This dependence arises because TiO bonds present a substantial kinetic and thermodynamic barrier to TiS2 formation. Lowering the sulfurization temperature is important to make smooth films, and to enable integration of TiS2 and related transition metal dichalcogenides—including metastable phases and alloys—into device technology.

Refractive Uses of Layered and Two-Dimensional Materials for Integrated Photonics

“…A variation on CVD and ssCVD is to use a chalcogen source (e.g., H 2 S or solid S) to convert a metal thin film to a LM compound thin film. − These are two-step processes, first involving deposition of the precursor thin film, often by evaporation or sputtering, followed by conversion in a CVD reactor. These two-step methods are scalable and reliable, but offer inferior layer number control and material quality than ssCVD, CVD, or MOCVD.…”

First-Principles Study on the Adsorption Characteristics of Corrosive Species on Passive Film TiO2 in a NaCl Solution Containing H2S and CO2

“…TiS 2 is mainly contained in the outer layer of the passive film. However, the source of some TiS 2 can be attributed to the competition of sulfur and oxygen for titanium bond orbitals, which is actually a central issue [49]. Since S and O are elements in the same main group, S more easily replaces O in passive film TiO 2 .…”

“…Since S and O are elements in the same main group, S more easily replaces O in passive film TiO 2 . That is, the nucleation and growth of partial TiS 2 is a process of replacing Ti-O bonds with Ti-S bonds [49]. Some researchers believe that the formation of sulfides on metals is much faster than the formation of corresponding oxides [50].…”

Pressure-modulated lattice structural evolution in TiS2

“…Water vapor and oxygen, as common atmospheric constituents, could be one of the many causes of the irreproducibility in the vapor phase growth of the Ti-S system. [10][11][12] It is noteworthy that the chemical vapor transition (CVT) technique can effectively solve this problem by adequately isolating water vapor and oxygen compared to CVD, which have been used in synthesizing TiS 2 and many other TMD materials. [13][14][15][16][17][18][19][20][21][22][23] Nevertheless, up to now, several challenges remain to be addressed in the CVT technique, such as undetermined questions involving reaction temperature, reaction time, and the length of the quartz-glass tube.…”