We report detailed studies of the low-temperature photoluminescence of Cd-related centers in InP. The samples consisted of Cd-diffused InP substrates as well as Cd-doped InP epitaxial layers grown by metalorganic chemical vapor deposition. Besides the previously identified 1.365-eV band, a new Cd-related band at a lower photon energy is reported. At 5.5 K, depending upon the excitation intensity, the peak position of this new band lies in the energy range 1.20–1.33 and 1.33–1.34 eV, respectively, in the substrates and in the epitaxial layers and it is broader compared to the 1.365-eV band. The peak position of the bands shifts to higher energy with increasing excitation intensity but the change in the peak energy per decade change in excitation intensity is much larger (50 meV) for the lower-energy band compared to the 1–2 meV shift for the 1.365-eV band. While the excitation dependence of the bands suggests a donor-to-acceptor pair recombination for their origin, we present arguments to show that the larger shift of the peak energy of the lower-energy band with excitation intensity is perhaps a consequence of the involvement of a deep donor in its origin as opposed to a shallow donor in the 1.365-eV band. In the case of InP:Cd substrates both the 1.365-eV band and the 1.20–1.33-eV band exhibit thermal quenching of luminescence above 100 K with an activation energy of 54±4 meV which is comparable to the ionization energy of 56 meV for the substitutional Cd acceptor, CdIn . From this we infer that both bands involve the CdIn acceptor in the recombination process. The identity of the deep donor in the 1.20–1.33-eV band and that of the recombination centers giving rise to the 1.33–1.34-eV band in the InP:Cd epitaxial layers are not known. In a preliminary comparison study on InP:Zn, similar, high- and low-energy Zn-related bands are observed. It is suggested that the deep donor is related to the group II impurity.

The bulk resistivity of Fe-doped metalorganic chemical vapor deposited grown epitaxial InP was determined from current-voltage and capacitance measurements made on Schottky-diode-like devices. The current-voltage data exhibit both an ohmic and a space-charge-limited regime, and the capacitance was found to be independent of applied bias. The electrical thickness was obtained from the capacitance using a relationship appropriate for current injection. Data for two samples representing both thin (∼1 μm) and thick (∼9 μm) epitaxial layers are presented. The resistivities were 6.5×107 Ω cm and 2.2×108 Ω cm.

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InP and In-oxide films have been deposited on quartz, GaAs, and InP substrates by excimer laser induced photodecomposition of (CH3)3InP(CH3)3 and P(CH3)3 vapors at 193 nm. The oxide film refractive index and stoichiometry are close to In2O3. Phosphorus incorporation in the films was greatly enhanced by focusing the laser beam to promote multiple-photon dissociation processes. These conditions also lead to enhanced carbon inclusion in the films, due to formation of species such as CH and CH2 in the gas phase. However, this carbon inclusion could be suppressed by focusing the beam onto the surface at normal incidence. In the irradiated zone InP could be deposited with P(CH3)3-to-(CH3)3InP(CH3)3 ratios of only ∼1:1. The technique offers several potential advantages over conventional metalorganic chemical vapor deposition, including lower temperature, enhanced rates, safer gases, and three-dimensional film composition control. Strong atomic In emission is observed in the gas phase above the depositing film, due to a multiple photon dissociation process. Gas phase fluorescence from P, CH, and C was also observed. These emissions give insight into the photodecomposition mechanism and also serve as a monitor of metalorganic precursor concentrations.