Effect of phosphoric acid chemical etching on morphological, structural, electrical, and optical properties of porous GaAs Schottky diodes

Schottky diode of porous n-GaAs layers have been prepared by chemical etching of n-type GaAs (100) substrates in (3 and 5) M of phosphoric acid (H3PO4) for 1 min. The influences of the acid molarity on the morphological, structural, electrical, and optical properties of GaAs samples were investigated. From EDX spectroscopy measurements identify the elements on the GaAs surface such as oxygen and phosphor. According to atomic force microscopy, the GaAs has the lowest surface roughness compared to the porosity sample prior to etching, which is to be expected given that the etching process normally results in roughness on the surface. X-ray diffraction studies confirmed the complex formation of Ga2O3 and As2O3 as a result of GaAs etching. Scanning electron microscopy is used to analyze the nano-features of porous GaAs, which makes it evident that these characteristics exist, particularly for high H3PO4 molarities. After being etched by 5 M H3PO4, the I–V characteristics of an Au/GaAs diode showed that it has a rectifying behavior with an ideality factor (n) of 2.42 and a barrier height (Φb) of roughly 1.08 eV in forward bias. As acid molarity rises, the built-in potential (Vbi) value rises as well. Photoluminescence spectroscopy (PL) was used to analyze the optical characteristics of the GaAs layer. Compared to GaAs, the sample that had been etched with 5 M H3PO4 showed the highest peak intensity.