A fe-si-al system ternary amorphous thin film with adjustable bandgap width and preparation method thereof

Abstract

The invention discloses a Fe-Si-Al ternary amorphous thin film with adjustable band gap width and a preparation method of the thin film, belonging to the technical field of semiconductor materials. The thin film comprises the following formula: Fe(1-x-y)SixAly, wherein x is not lower than 50at.% and not higher than 70at.%; y is not lower than 1at.% and not higher than 11at.%; when the total amount of (x+y) is changed to 75at.% from 60at.%, the band gap width of the thin film can be adjusted to 0.65eV from 0.45eV; and the structure of the thin film is an amorphous structure. The film has the following advantages that (1), the Fe(1-x-y)SixAly thin film is a ternary amorphous thin film with adjustable band gap width from 0.45 eV to 0.65eV; Al not only affects the band gap width, but also increases the amorphous forming ability by increasing a component element film; (2), the total amount of (Si+Al) in the film can be conveniently adjusted by changing the quantity of Fe4Alz alloy sheets and the z value in a combined sputtering target to obtain different band gap widths; (3), the thin film is kept amorphous, so that the uniformity of the components and performances can be ensured, and the problems such as lattice mismatch, and multi-phase mixing and the like in the amorphous thin film preparation are effectively avoided. The Fe-Si-Al ternary amorphous thin film with adjustable band gap width provided by the invention is suitable for manufacturing narrow band-gap semiconductor apparatuses such as an infrared detector.

Description

technical field [0001] The invention relates to an Fe-Si-Al ternary amorphous film with adjustable band gap width and a preparation method thereof, belonging to the technical field of semiconductor materials. Background technique [0002] Semiconductor metal silicides are one of the materials used in solar cells. They have excellent compatibility with single crystal silicon technology, and have metal conductivity, high thermal stability, oxidation resistance and superior mechanical stability. Silicides have also attracted great interest due to their superior environmental friendliness, especially the transition metal silicide β-FeSi 2 , its raw materials Fe and Si are both rich and non-toxic, and can synthesize various relatively safe devices. More importantly, β-FeSi 2 It has a direct band gap of 0.83~0.87eV, and has a large optical absorption coefficient for infrared wavelengths (α > 10 -5 cm -1 ,1.0eV), the theoretical photoelectric conversion efficiency can reach ...

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Problems solved by technology

The crystals are also prone to defects such as stacking faults and twins, so it is difficult to obtain high-quality and pure β-FeSi 2 Material

[0004] (2) β-FeSi 2 When used in the field of optoelectronics, most of the thin films are prepared on the basis of single crystal Si, but there is a large film-base mismatch problem, resulting in many of its properties failing to meet theoretical expectations.

[0005] (3) Binary β-FeSi currently prepared using different methods 2 material, whose bandgap width varies around 0.87eV, is slightly different, but cannot be modulated

Crystalline ternary FeSi after adding the third component 2 Type materials are prone to phase separation. Although the bandgap width can be modulated in a wide range, it increases the instability of the structure and further deteriorates the situation of multiphase mixing.

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