Zn 3 N 2 polycrystalline films with n+-type conductivity have been grown by metalorganic chemical vapor deposition and rf-molecular beam epitaxy with carrier concentration in the range between 1019 and ∼1020cm−3. Oxygen contamination without an intentional doping was found to be a cause of high electron concentration, leading to a larger band-gap energy due to Burstein-Moss shift. The significant blue shift of the optical band gap Eopt with increasing carrier concentration ne obeys the relation Eopt=1.06+1.30×10−14ne2∕3. This evaluation enables the conclusion that the actual band-gap energy of Zn3N2 is 1.06eV. Electron effective mass m* for Zn3N2 has been deduced from Fourier transform infrared reflectivity measurements to be (0.29±0.05)mo.

We report on the results of Hall effect and photoluminescence (PL) in n-type Zn3P2 grown by molecular beam epitaxy. The Zn3P2 thin films indicated n-type conductivity instead of the usual p-type conductivity due to a strong self-compensation effect with Hall mobility and carrier concentration of 3–7×103 cm2/Vs and 3–9×1010 cm−3 at room temperature, respectively. Donor levels of 0.01 and 0.73 eV from the conduction band were identified by resistivity and Hall effect measurements. The PL spectra show donor-acceptor pair emission near 1.41 eV at 20 K ascribed to an acceptor level of 0.26 eV from the valence band.

Deep levels in iron-doped n-type silicon have been investigated by deep-level transient spectroscopy (DLTS). Three deep levels of Ec−0.29 eV (E1), Ec−0.36 eV (E2), and Ec−0.48 eV (E3) were observed. The concentration of E1 and E2 levels increased during the storage at room temperature. The depth profile of the E3 level concentration indicates the out-diffusion and precipitation of the defects related to the E3 level. In addition, after annealing at 80 °C for 30 min, the E2 and E3 concentrations decreased and then recovered at room temperature. These results suggest that the defects related to these levels are mobile during quenching and storage at room temperature. The temperature dependence of the E3 level concentration shows a formation energy of about 2 eV, which is smaller than that of interstitial iron, and the E3 level concentration is two orders of magnitude lower than the concentration of interstitial iron. The origins of these levels are probably loosely associated iron-related complexes such as iron-acceptor pairs.

We report the first epitaxial growth of Zn3P2. The Zn3P2 epitaxy was obtained on (100) GaAs and ZnSe/GaAs by metalorganic chemical vapor deposition at growth temperatures of 350–400 °C and V/II ratios above 0.8 using dimethylzinc and PH3. The stoichiometry was assessed by x-ray photoelectron spectroscopy at Zn/P=1.5. A Hall mobility of 310 cm2/Vs at 300 K was obtained with a hole concentration of 3.5×1016 cm−3 for Zn3P2 grown at 380 °C. The absorption edge deduced is 1.51 eV at 300 K. Photoluminescence data suggest four acceptor levels (45, 65, 86, and 104 meV at 12.8 K).

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The electro-optical coefficient r 41 of Bi4Ge3O12, corresponding to the sensitivity of the optical voltage sensor, and the temperature dependence of response characteristics to applied step voltage are studied. From these measurements, two kinds of dc drift are found to exist in Bi4Ge3O12 crystals. One is found to be due to the relaxation of the piezoelectric polarization (type (a)), and the other is explained as the deduction phenomenon by the thermally induced space-charge field (type (b)). By correcting for dc drift of type (a), the accurate value of r 41=1.09×10-12 m/V is obtained at 855 nm wavelength.