CdTe:Mn was prepared by implantation of CdTe with 200keV Mn ions with a dose of 5 31016cm22, which produced an insulating layer in the surface region. Ferroelectric characterization of the implanted sample revealed a clear hysteresis in its polarization-voltage curves. The remnant polarization of CdTe: Mnamounts to 0.64mC/cm2 at 400Hz, and it decreases with increasing temperature in a continuous and diffusive manner. Capacitance measurement demonstrated a maximum capacitance at 140℃, and fitting of the data with Curie-Weiss law shows the occurrence of a second-order-type phase transition. The ferroelectricity is accounted for by the cation size difference in CdTe: Mn.

CdZnTe has been characterized by means of polarization-field hysteresis and current-voltage measurements. The CdZnTe is shown to be ferroelectric with polarization endurance up to 107 poling cycles. The polarization is significantly influenced by free carriers and can be switched by light illumination. The capacitance of CdZnTe consists of ferroelectric and depletion components. On the other hand, electrical conduction in the CdZnTe is modulated by the polarization, leading to hysteresis in the current–voltage characteristics. Writing and reading measurement has shown a reading-current difference of 0.015 mA at a nondestructive voltage for the binary digits.

GaN metal-oxide-semiconductor (MOS) capacitors were fabricated by using Ga oxide formed by photoelectrochemical oxidation of GaN. The electrical properties of the MOS structures as characterized by capacitance-voltage measurement were found to be dependent on the oxidation time and posttreatment. Positive flatband voltage was observed in devices with thin oxide layers indicating the existence of negative oxide charge. Very thin oxide exhibits high capacitance and reverse leakage, which can be reduced by rapid thermal annealing (RTA). Passivation of the interface by RTA is partially responsible for the improvement. Thicker oxide layers exhibit improved electrical properties. Low density of interface states (1011eV21cm22) was obtained in the Ga-oxide/GaN structure grown under optimized conditions.

GaN epilayers grown by molecular beam epitaxy were photoelectrochemically (PEC) oxidized in an aqueous KOH solution. The oxidation effect was investigated by defect-related photoconductivity and photoluminescence. The PEC treated GaN show decreased extrinsic photoresponse and concentration of deep level states in comparison with the as-grown sample. The PEC process also results in enhanced donor-bound exciton photoluminescence at 3.47eV and restrained 3.4eV band. No strain is detected in the PEC oxidized GaN. The 3.4eV band is related to structural defects instead of oxygen impurities. Rather, the defects can be passivated by the PEC oxidation.