Defect studies in CuBIIIC chalcopyrite compounds using the ion channeling technique

Based on simple approximations the backscattering minimum yield is estimated for axial ion channeling in perfect crystals of six CuB^IIIC chalcopyrite compounds. The results obtained for CuInSe₂ are compared with experimental channeling spectra. Point defect concentrations up to about 10²¹ cm⁻³ are estimated for CuInSe₂ single crystals grown by the vertical Bridgman method. A simple power law is found for the fluence dependence of the damage density in oxygen implanted CuInSe₂ single crystals.     

Electrical properties of AgGaSe2 epitaxial layers

Epitaxial layers of AgGaSe₂ with thicknesses in the range from 50 to 70 nm were deposited onto (111)A-oriented semi-insulating GaAs substrates by flash-evaporation in the substrate temperature range T_S = 825 … 900 K. Films grown at T_S ≦ 850 K are n-type conducting whereas p-type conductivity was observed at T_S ≧ 875 K. In the p-type samples two acceptor states with ionization energies of 60 and 410 meV were found from an analysis of the electrical measurements.     

Optical Properties of CuInSe2 Thin Films Prepared by R.F. Sputtering

The optical absorption of r.f. sputtered CuInSe₂ thin films was studied in the photon energy range from 1 to 3 eV. The gap energy and the spin-orbit splitting are found to be (1.01 ± 0.01) eV and (0.24 ± 0.02) eV, respectively. From the photon energy dependence of the absorption coefficient it is concluded that the heavy and light hole bands are parabolic whilst the split-off band contains terms linear in the wavevector. The optical transition probability for valence band- to- conduction band transitions is estimated to be (10.8 ± 1.0) eV which yields an admixture of copper d states to the valence band of (30 ± 8) %.     

Deposition of InP on GaAs Substrates in the InP/PCl3/H2 System

Vapour phase epitaxial layers of InP were deposited onto (111)A-, (111)B-, (001)-, and (110)-oriented GaAs substrates in the InP/PCl₃/H₂ system using a close-space technique. It is shown that the dependence of the layer quality on the substrate orientation is due to differences in the initial growth stages. Results on the growth rates and the electrical properties of the layers are reported.