Λ-modulated photoemission of ZnAs2 and CdP4 semicorductors

Investigated is the spectral photoemission distribution from the ZnAs2 and CdP4 surface in combination with the Λ-modulated photoemission and Λ-modulated photoconductivity. The photoemission investigations have been performed in the vacuum (2-3)x10-9 torr, the work function being reduced by the introduction of Cs, Cs-O up to obtaining the maximum emission current. It has been found that the emission threshold for CdP4 starts in the region of 0.9 - 1.2 eV, for ZnAs2 - in the region of 1.0 - 1.1 eV. In the CdP4 and ZnAs2 photoemission Λ-modulated spectra detected are the peaks testifying to a complex zone structure of these crystals in the region of the minimum of the interzonal gap. The data given agree with the results of the reflection spectra. The peak E'1 (1.12 eV), that does not reveal itself in the reflection spectra, is present in the differential photoemission spectra. The spectral distribution of the Λ-modulated photoemission possesses slighter peculiarities in the energy region less than 1.5 eV