Ferroelectric properties of (Al,Ga)InP$_2$ alloys

Spontaneously ordered AlGaInP$_2$ layers with CuPtB structure and ordering degree $\eta$ = 0.16–0.46 were obtained by MOVPE epitaxy on GaAs substrates. Using the Kelvin probe microscopy method, the dependence of the layer surface potential on $\eta$ was found. Comparative analysis of the behavior of CuPt$_{\mathrm{B}}$-AlGaInP$_2$ and CuPt$_{\mathrm{B}}$-GaInP$_2$ alloys under mechanical stress showed the presence of a martensitic transition and the associated change in the surface potential in both materials. The effect of Al on increasing the value of the built-in electric field in the stressed state of the crystal lattice and reducing the recovery time (relaxation) of the layer was found.