Synthesis of SnS Thin Films by Atomic Layer Deposition at Low Temperatures

Abstract

Two-dimensional (2-D) metal chalcogenides have received great attention because of their unique properties, which are different from bulk materials. A challenge in implementing 2-D metal chalcogenides in emerging devices is to prepare a well-crystallized layer over large areas at temperatures compatible with current fabrication processes. Tin monosulfide, a p-type layered semiconductor with a high hole mobility, is a promising candidate for realizing large-area growth at low temperatures because of its low melting point. However, tin sulfides exist in two notable crystalline phases, SnS and SnS2. Therefore, it is imperative to control the oxidation state of Sn to achieve a pure SnS film. Here, the synthesis of SnS thin films by atomic-layer-deposition (ALD) is demonstrated using bis­(1-dimethylamino-2-methyl-2-propoxy)­tin­(II) and H2S as Sn and S sources, respectively, over a wide temperature window (90–240 °C). Impurities such as carbon, oxygen, and nitrogen were negligibly detected. The morphological evolution of plate-like orthorhombic SnS grains was observed above 210 °C. Moreover, properties of thin film transistors and gas sensors using SnS films as the active layers were investigated. The SnS ALD process would provide promising opportunities to exploit the intriguing properties of the 2-D metal chalcogenides for realizing emerging electronic devices.

Development of a SnS Film Process for Energy Device Applications

“…In that research, the growth rate of the ALD SnS process was 0.9 Å/cycle, and the deposition of a 500 nm thick SnS film required a long deposition time [2,22]. Other ALD SnS studies have showed lower growth rates of 0.24 to 0.36 Å/cycle [23][24][25][26]. The growth rate of general films deposited with ALD is about 1 Å/cycle, but the growth rates of ALD-deposited SnS films are lower than 1 Å/cycle.…”

Effect of Temperature and Capping Agents on Structural and Optical Properties of Tin Sulphide Nanocrystals

“…Tin sulphide exists as a orthorhombic crystal like distorted NaCl structure in which the Sn anion is surrounded by six S atoms separated by Van der Waals forces [2]. SnS nanoparticles have unique properties suitable for a wide range of nanoscale electronics, photodetectors, sensing devices, infrared detectors, storage of energy, and fabrication of photovoltaics [9][10][11][12][13][14][15][16][17][18][19][20]. SnS possesses photoconducting, photocatalytic, and Pieter effects making them useful in thermoelectric cooling, thermoelectric power generation, and near-infrared photoelectronics [16,[21][22][23][24][25].…”

Investigations on the parameters limiting the performance of CdS/SnS solar cell

“…The direct way of conversion of solar energy to electrical energy is photovoltaics (PVs). Although, SnS could be prepared by number of vacuum and nonvacuum techniques, [5][6][7][8][9][10][11][12] in our present work, absorber (SnS) films were prepared by thermal evaporation technique to obtain adhesive, uniform, and high-quality films. 1 Recent trends of thin-film solar cells were developed on polycrystalline CdTe and CIGS.…”

“…In this context, a simple binary absorber material, tin monosulfide (SnS) whose constituent materials are nontoxic, abundantly available with a direct band gap of 1.3 eV is selected as an absorber layer in our solar cells. Although, SnS could be prepared by number of vacuum and nonvacuum techniques, [5][6][7][8][9][10][11][12] in our present work, absorber (SnS) films were prepared by thermal evaporation technique to obtain adhesive, uniform, and high-quality films. In the view, that a novel absorber in conjunction with the good buffer layer will yield better efficiencies in the solar cells, the impact of the buffer layer is of significance in the present work.…”