Fine structured low temperature luminescence of CdP₂

Abstract

semiconductors show interesting optical properties (1 to 3 and references therein). In this note we report photoluminescence spectra of tetragonal CdP2 single crystals at 4.2 K which show much more fine structure than the spectra published so far (3, 4).CdP single crystals were grown from the gaseous phase (2) without intentional doping. They were immersed in liquid He and excited with the light of a high pressure mercury lamp. 2 With low spectral resolution our spectra a r e identical with those of (4): two broad bands peaked a t 2.09 and 1.85 eV. With high resolution the high energy part of the 2.09 eV peak shows pronounced fine structure (Fig. 1). This fine structure is very similar to the near gap luminescence of tetragonal ZnP an indirect gap semiconductor with E = 2.200 eV a t T = 4.2 K (1). In ZnP this luminescence is 2' g 2 i ( n m ) Fig. 1. Photoluminescence spectrum of CdP2, T = 4.2 K

Luminescence at the axial centers of CdP2-D48 crystals

“…These wavelengths are located in the region of the edge absorption beginning, where there is a change in electronic transitions (indirect, direct), responsible for edge absorption. As mentioned above, the optical properties of the tetragonal CdP 2 have been studied in many research works, where the indirect nature of the minimum energy gap and the magnitudes and the energies of the phonons participating in the transition are determined [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ].…”

“…Cadmium diphosphide (CdP 2 ) belongs to the group of wide-gap А II В V semiconductor materials and possess a natural gyrotropy and anisotropy [ 1 , 2 , 3 ]. Reflection, absorption and photoluminescence spectra in the electronic transitions and vibrational modes region are observed [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. The values of the nonlinear polarization and gyrotropy of CdP 2 are higher than those of other crystals, providing an effective stabilization of the radiation field simultaneously in space (cross section) and in time [ 13 , 14 , 15 , 16 ].…”

“…[ 19 , 20 ] and the possibility of creating magneto-optical modulators based on CdP 2 , sensitive elements for measuring magnetic field induction was demonstrated. On the basis of CdP 2 crystals a technology for obtaining p-n junctions of surface-barrier diodes has been developed [ 2 , 3 , 5 , 6 , 7 , 8 , 9 ]. Photoelectron emitters and photodiodes [ 21 , 22 , 23 ], electric switches [ 24 , 25 ] and Zener diodes [26] have been developed on the basis of the CdP 2 single crystals.…”

“…24 atoms and the number of phonon branches is 72 in the general case. The selection rules for vibrational modes are different for different light waves polarizations, which affects the dielectric constants and other parameters [ 7 , 8 , 12 , 13 ].…”

“…The technology of Me-CdP 2 Schottky diodes obtaining has been developed, electric and photoelectric characteristics of diodes have been investigated, where In, Cu, Pt, Ga, Pb, Sb, Ag, Te, Au, Hg were used as metals. The parameters and properties of Schottky diodes are determined in a wide range of temperatures and light waves [ 2 , 3 , 5 , 6 , 7 , 8 , 9 ].…”