One-step H₂S reactive sputtering for 2D MoS₂/Si heterojunction photodetector

Abstract

A technique for directly growing two-dimensional (2D) materials onto conventional semiconductor substrates, enabling high-throughput and large-area capability, is required to realise competitive 2D transition metal dichalcogenide devices. A reactive sputtering method based on H2S gas molecules and sequential in situ post-annealing treatment in the same chamber was proposed to compensate for the relatively deficient sulfur atoms in the sputtering of MoS2 and then applied to a 2D MoS2/p-Si heterojunction photodevice. X-ray photoelectron, Raman, and UV–visible spectroscopy analysis of the as-deposited Ar/H2S MoS2 film were performed, indicating that the stoichiometry and quality of the as-deposited MoS2 can be further improved compared with the Ar-only MoS2 sputtering method. For example, Ar/H2S MoS2 photodiode has lower defect densities than that of Ar MoS2. We also determined that the factors affecting photodetector performance can be optimised in the 8–12 nm deposited thickness range.

A review of molybdenum disulfide (MoS2) based photodetectors: from ultra-broadband, self-powered to flexible devices

“…Research activities on MoS 2 based photodetectors is emerging on a fast pace. [446][447][448][449][450][451] The large family of 2D materials can be explored for developing photodetection devices. For example, 2D TMDs such as MoSe 2 , MoTe 2 , WS 2 , WSe 2 , PtS 2 , PtSe 2 , PtTe 2 , PdS 2 , PdSe 2 , PdTe 2 , GeS 2 , GeSe 2 , HfS 2 , TiS 2 , FeS 2 , CoS 2 , NiS 2 , SnS 2 , MoSe 2 , NbSe 2 , TaSe 2 , NiSe 2 , FeSe 2 , and CoSe 2 can be explored for developing new vdWHs for high-performance photodetectors.…”

Sputtered 2D transition metal dichalcogenides: from growth to device applications

“…Although it is not very easy to find target materials for any oxides, nitrides or chalcogenides, it is possible to grow reactively any oxide ornitride materials from the elemental targets by just inserting a related gas into growth chamber. It might be even possible to grow reactively chalcogenides by using H 2 S [24]or H 2 Se [25] gases. In reactive sputtering, oxygen or nitrogen gas can be supplied into the chamber before the growth process.…”

“…It is possible to classify these strategies into two parts; single (or one)-step and two-step growths. For the one-step growth method, the easiest is to grow by the reactive sputtering withH 2 S gas from a TMDC target [24]. For example, MoS 2 target is used for reactive sputtering in Ar/H 2 S mixed gas environment and it has shown that an improved crystal and stoichiometric properties is obtained in sputtered 2D layers in mix Ar/H 2 S gas environment.…”

Co-deposition of MoS2 films by reactive sputtering and formation of tree-like structures

“…Multi-layer TMDC has lower absorption coefficient due to its indirect bandgap, but its large cross-section of chemically active edge terminated sites can be used for other applications, such as hydrosulfurization [7], hydrogen evolution reaction [8], or NO 2 and ethanol detection [9]. For transition from the proof-of-concept to scalable production, various bottom-up fabrication methods, such as chemical vapor deposition (CVD) [10,11], metal-organic CVD (MOCVD) [10,11], molecular beam epitaxy (MBE) [10,11], atomic layer deposition [11,12], and sputtering [11,13], have been explored. From these studies, it has been found that lateral growth occurs when there is sufficient lateral diffusion with minimal desorption of chalcogen, either by increasing the growth temperature for high surface mobility of transition metal [10] or by slowed growth rate [11].…”

“…Reactive sputtering offers good composition control since the reactants are simultaneously and independently supplied in gas phase during the growth. Conventional sputtering-based MoS 2 films fabrication uses two-step methods: sputtered molybdenum (Mo) [16,17] or MoS 2 [18][19][20][21][22][23] films are sulfurized under sulfur (S) gas [12] or H 2 S gas [13] or annealed [18,21,22]. Reactive sputtering in this study does not require post-annealing process.…”