Growth of PtSe2 few-layer films on NbN superconducting substrate

Abstract

Few-layer films of transition metal dichalcogenides have emerged as promising candidates for applications in electronics. Within this group of 2D materials, platinum diselenide (PtSe2) was predicted to be a compound with one of the highest charge carrier mobility. Recently, the successful integration of group III–V nitride semiconductors with NbNx-based superconductors was reported with a semiconductor transistor grown directly on a crystalline superconductor. This opens up the possibility of combining the macroscopic quantum effects of superconductors with the electronic, photonic, and piezoelectric properties of the semiconducting material. Here, we report on the fabrication of a few-layer PtSe2 film on top of an NbN substrate layer by selenization of pre-deposited 3 nm thick Pt layers. We found the selenization parameters preserving the chemical and structural integrity of both the PtSe2 and NbN films. The PtSe2 film alignment can be tuned by varying the nitrogen flow rate through the reaction chamber. The superconducting critical temperature of NbN is only slightly reduced in the optimized samples compared to pristine NbN. The carrier mobility in PtSe2 layers determined from Hall measurements is below 1 cm2/V s.

Effect of the crystallographic c-axis orientation on the tribological properties of the few-layer PtSe2

“…1 shows the GIWAXS patterns for the low-temperature PtSe 2 films as well as high-temperature films synthesised on the sapphire substrate with different thickness of the pre-deposited Pt layer. GIWAXS pattern with a 001 diffraction peaks at the reciprocal lattice vector length |q001| ≈ 1.15-1.18 Å -1 [36] are observed for all the films. PtSe 2 layers on the sapphire substrate obtained by selenization of the pre-deposited 3-nm thick Pt layer at low temperature showed two symmetrical 001 diffraction spots at q xy ≈ 1.17 Å -1 (Fig.…”

Optical Characterization of Few-Layer PtSe2 Nanosheet Films

“…Details on growth conditions and preparation methodology can be found in our previous publications on PtSe 2 . 23 , 37 , 38 …”

“…Details on growth conditions and preparation methodology can be found in our previous publications on PtSe 2 . 23,37,38 A confocal Raman microscope (Alpha 300R, Witec, Germany) with an excitation wavelength of 532 nm was used for Raman scattering measurements. All Raman spectra were collected at room temperature using a 50× objective coupled to a 100 μm optical fiber serving as a confocal pinhole.…”

“…Two series of Pt films were then annealed in a chemical vapor deposition (CVD) chamber with 0.1 g of 99.999% pure selenium powder at the annealing temperatures of 400 and 600 °C. Details on growth conditions and preparation methodology can be found in our previous publications on PtSe 2 . ,, …”