Optoelectronics applications of electrodeposited p- and n-type Al₂Se₃ thin films

Abstract

In this paper, energy band gaps and electrical conductivity based on aluminum selenide (Al2Se3) thin films are synthesized electrochemically using cathodic deposition technique, with graphite and carbon as cathode and anode, respectively. Synthesis is done at 353 K from an aqueous solution of analytical grade selenium dioxide (SeO2), and aluminum chloride (AlCl2·7H2O). Junctions-based Al2Se3 thin films from a controlled medium of pH 2.0 are deposited on fluorine-doped tin oxide (FTO) substrate using potential voltages varying from 1,000 mV to 1,400 mV and 3 minutes −15 minutes respectively. The films were characterized for optical properties and electrical conductivity using UV-vis and photoelectrochemical cells (PEC) spectroscopy. The PEC reveals a transition in the conduction of the films from p-type to n-type as the potential voltage varies. The energy band gap reduces from 3.2 eV to 2.9 eV with an increase in voltage and 3.3 eV to 2.7 eV with increase in time. These variations indicate successful fabrication of junction-based Al2Se3 thin films with noticeable transition in the conductivity type and energy band gap of the materials. Consequently, the fabricated Al2Se3 can find useful applications in optoelectronic devices.

A review of novel methods to improve the optical and electrical properties of n-type and p-type sulphides and oxides: leading the frontiers of semiconductor technology

“…The bandgap controls how much energy is needed to excite an electron from the valence band to the conduction band, and hence how much light the material can absorb and emit [16,36]. For applications requiring higher energy photons, like LED lighting, materials with a wider bandgap are more suited, whereas materials with a narrower bandgap are better suited for applications requiring significant absorption of lower energy photons, like solar cells,since they require a high hole concentration [37].…”

Effect of pH variation on the optoelectronic properties of electrodeposited Al₂GaSe₃ ternary compound semiconductor

“…Moreover, aluminum selenide (Al 2 Se 3 ) has been known to be a promising material because they have direct band gap energy, better charge transport, good absorption co-efficient and high transmittance (Olubosede et al, 2020). As well, Al 2 Se 3 has been said to be a good window layer material that is useful for the formation of hetero -junction together with absorber layer materials like lead sulfide and cadmium telluride (Faremi et al, 2021). However, GaSe has weak mechanical properties, high dislocation density and possesses high equilibrium partial pressures of Se (Ni et al, 2013).…”