Investigation of the porous GaP layers'
chemical composition and the quality
of the tests carried out
Authors: Vambol S. , Vambol V. , Suchikova Y. , Bogdanov I. , Kondratenko O. 
Published: May 2018

Purpose: The purpose of this study is to establish the quality of tests for determining the
chemical composition of the porous surface obtained by the method of electrochemical
etching, based on the indicators of convergence and reproducibility of the results.
Design/methodology/approach: The method of electrochemical etching was used to
obtain layers of porous gallium phosphide, which can be used as buffer layers for nitrides
formation on their basis. Por-GaP was formed in a solution of hydrofluoric acid at a current
density of j =100 mA/cm2, etching was carried out for 20 minutes. The resulting structures
sulfide passivation was carried out, thus avoiding the formation of an oxide film on the
samples surfaces. For this purpose, porous gallium phosphide samples were kept in a
sulfide solution for 10 minutes and dried in a stream of nitrogen. The chemical composition
of the porous GaP surface layers has been investigated. To do this, the method of electronprobe
INCA Energy microanalysis was used. The research was carried out on the entire
surface of the sample in order to calculate the total spectrum of the elemental composition
of the sample under study.
Findings: It was established that during anodizing, the stoichiometry of the crystals
investigated did not shift significantly towards the excess of gallium atoms. Oxygen is present
at an insignificant concentration of 0.3%. This indicates the effectiveness of conducting
the sulfide passivation of the sample surface following the electrochemical treatment. The
presence of fluorine atoms that appeared on the surface as a result of the reaction with the
electrolyte during etching, is observed in extremely low concentration. Experimental studies
have shown that the sample chosen can be used as a standard enterprise sample when
analyzing the chemical composition of the surface of porous gallium phosphide due to its
convergence, reproducibility, homogeneity. In addition, the given method for determining the
standard sample can be applied to other porous semiconductors. Conducting such studies
is an important technological task that will allow us to create a series of standard samples
of porous semiconductors of A3B5 group.
Research limitations/implications: The research was carried out for porous gallium
phosphide samples synthesized in the solution of hydrofluoric acid, though, carrying out of
similar experiments for por-GaP obtained in other conditions, is necessary.
Practical implications: The studies of the reproducibility and convergence of the
experiment have an important practical significance, since it is the reproducibility of the
experiment results that is the main problem to modern material science, all the more to
nanoengineering. Therefore, the technique proposed, will allow the synthesis of por-GaP
layers with adjustable properties, will facilitate their widespread implementation in the real
sectors of industry. The obtained porous layers can be used as standard samples.
Originality/value: The main problem in the nanostructures synthesis is the adjustability
of properties. The technique presented allows to form stable layers of the porous gallium
phosphide with the surface chemical composition known in advance. In addition, carrying
out the sulfide passivation allows to stabilize por-GaP properties, which is an important
process task. For the first time, a study of the presented technique as to convergence,
reproducibility and homogeneity, was conducted.