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In Ref. 1 the photoluminescence due to electron-hole recombination via deep donor-acceptor pairs ͑DAP's͒ in CuGaSe 2 and in CuInS 2 crystals was investigated experimentally. For the emission spectrum analysis it was stated that, for otherwise similar pairs but with the donor-acceptor separation varying-r 1 and r 2 , respectively-a difference ⌬E 12 in the emission energies would be expected

Photoluminescence (PL) of CuGaSe2 and CuInS2 single crystals, either as grown or Cu annealed, reveals a broad and clear deep emission band at hν≈Eg−0.6 eV. In both of these as-grown materials this band has a similar doublet structure with the two D1,D2 subbands separated by about 100 meV. After the Cu annealing all samples became highly compensated and an additional deep PL band (W band) appeared on the high energy side of these D bands. This suggests a closely similar origin of the emission for the both materials. By a straightforward model calculation we show that the changes in the shape and intensity of these emission bands—due to variation of temperature, excitation intensity or due to the Cu annealing—are well explained if we assume that the D1 and D2 PL subbands originate in the recombination between the closest and the second closest donor–acceptor pairs, with the essential ingredient of the emission center being an interstitial donor defect, i.e., either Cui or Gai in CuGaSe2 and Cui or Ini in CuInS2. The W band in both compounds appears to be due to the recombination of an electron from this deep donor level with a hole in a deep localized state of the valence band tail.

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We have studied the photoluminescence band shape of the 1.36 eV (Z‐band) and the 1.32 eV (Z′‐ band) PL bands in high purity low‐temperature‐grown n‐type bulk polycrystalline CdTe as a function of the excitation power and temperature. Both bands have a nonsymmetrical shape with a gradual decrease on the high‐energy side but the variation of the shape with temperature and excitation power is different for Z‐ and Z′‐bands. Both bands have the same temperature quenching activation energy ET = 35 meV. On the basis of our investigations we assign the 1.32 eV emission to a free‐to‐bound recombination near dislocations and the 1.36 eV emission to a DA emission near the same dislocation. Both bands are related to a shallow acceptor EA = 35 meV (probably Li or Na), whose concentration in the bulk is quite low. The Z‐band is also related to a deep donor (ED ≥ 200 meV), probably of intrinsic origin.