DOI: 

Optoelektron. napìvprovìd. teh. 61, 87-102 (2026)

I.M. Matiyuk, V.V. Tetyorkin, O.Yu. Kolyadina, A.A. Yevtukh, A.T. Voroschenko. 

Diagnostics of semiconductor crystals and heterostructures by modulation electroreflection spectroscopy method (review) 

The review article analyzes the electroreflection method, in which the signal is formed by modulating the alternating electric field of monochromatic unpolarized or linearly polarized light reflected from the surface of the studied crystalline structure of semiconductors. The method allows to detect direct optical zone-zone transitions at critical points of Brillouin zones (van Hove features) of a particular crystalline semiconductor or its micro- or nanocrystalline inclusions in an amorphous matrix. The thickness of the reflecting layer of the crystal in the region of interband optical transitions usually does not exceed 100 Å.

An experimental setup for studying electroreflection is described in detail. Two measuring cells were constructed: one for measurements in the transparency region of the aqueous electrolyte solution (5.6 to 1 eV) and one for measurements in the region of strong light absorption by the aqueous electrolyte solution due to the formation of a thin capillary layer (1 to 0.6 eV). Provision is made to eliminate the constant component of reflection from the front wall of the cells and extract the signal from the constant component of reflection from the sample, which is especially important for weak measured signals.

New data on direct optical transitions in CdAs2, ZnAs2 and InSb are obtained.  Some known transitions are measured with greater accuracy. The influence of surface treatments on the parameter Г, which is an integral characteristic of the scattering of charge carriers on defects, is analyzed. It is shown that with all the surface treatments of ZnAs2 single crystals used, mechanical compressive stresses arise: the smallest on chipped surfaces, increase on chemically cut surfaces, even greater on diamond wire cut surfaces, and significantly increase for polished surfaces. The coefficient of change in the energy of the direct optical transition from pressure dE/dP has a positive sign. With all the surface treatments studied, the scattering of charge carriers excited by light on near-surface defects increases, and most of all after mechanical grinding. It has been established that during mechanical grinding and polishing on the surface of ZnAs2 single crystals of p-type conductivity, n-type inversion layers are formed, which are associated with the donor nature of defects that arise during plastic deformation. After chemical etching, non-stoichiometric point defects may form in the surface layer, which, however, do not change the type of conductivity and cause only minor elastic deformations.

Keywords: modulation spectroscopy, electroreflection, surface defects, surface treatment, CdAs2, ZnAs2, heterostructures SiCN/InSb.