Growth Study of New Complex Oxide PbO_xSe_1–x Thin Films by Oxygen Plasma-Assisted Molecular Beam Epitaxy

Abstract

In this work, we introduce the growth of a new complex oxide lead oxy-chalcogenide (PbO x Se 1−x ) thin film using an oxygen plasma-assisted molecular beam epitaxy method. Freshly cleaved BaF 2 (111) wafers were used as the substrates for this growth study. Systematic characterization of X-ray diffraction peaks, Raman shifts, absorption spectra, scanning electron microscopic imaging, and Hall measurements were conducted to elucidate the structural, optical, and electric properties of the as-grown PbO x Se 1−x thin films. Specifically, X-ray diffraction measurements revealed that PbO x Se 1−x films maintained the same rock-salt crystal structure as the PbSe semiconductor, but a slight shift in the lattice parameter was observed. A blue shift in the optical absorption edge also suggests that the inclusion of oxygen atoms led to the formation of a ternary compound crystal structure. Furthermore, all PbO x Se 1−x thin films were observed to be polycrystalline in nature and displayed preferred [100] orientated grains. Slight variations in LO and TO phonon peak positions were also observed under Raman spectroscopy, signifying the presence of lead−oxygen bonding. This new type of complex oxide thin film has never been reported and could potentially be used to develop advanced optoelectronic devices, including mid-infrared photodetectors and light-emitting devices.

Low-cost uncooled MWIR PbSe quantum dots photodiodes

“… 41 A recent study has also found the formation of ternary PbO x Se 1− x structure, which may form as a result of oxygen atom incorporation. 42 This surface oxygen passivation, which is always employed to enhance the photoresponsivity of lead-salt detectors, 43 is another reason for the coarsening of the film's surface when annealed at 673 K.…”

Facile sensitizing of PbSe film for near-infrared photodetector by microwave plasma processing

“…When making devices from materials, it is often necessary to sensitize PbSe under an oxygen/halogen atmosphere to improve the stability of devices and reduce noise, which is a critical process that determines the performance of photodetectors. [10][11][12][13][14][15] For a long time, scientists worldwide have researched the sensitization method and sensitization mechanism of PbSe based devices. [16][17][18][19] For example, Humphrey and Scanlon reported that the p-n type of PbSe film can be converted by doping the halogen group during thermal sensitization.…”