CdZnTe is nowadays a reference semiconductor for detection of X and ?-radiation. The electrical properties of CdZnTe-based (CZT) detectors are strongly affected by the surface and subsurface defects, which can cause an excessive surface leakage current (SLC). This issue strongly degrades the sensor performance and becomes critical for multi-stripes detectors, where the stripes are kept at different voltage potentials in order to shape the electric field inside the semiconductor material.In this work, we propose a passivation method based on the deposition of a thin AlO film on the non-metallized CZT surface. To demonstrate the effectiveness of the method, we fabricated several 19.4x19.4x5 mm CZT multi-stripes detectors with 48 parallel Au stripes on the anode face (12 collecting anodes and 36 drift stripes) and subsequently deposited a AlO polycrystalline thin film on the CZT surface between the stripes. AlO deposition was achieved by sputtering technique. Electrical characterization of surface leakage current before and after AlO is presented.AlO coating treatment allowed us to obtain exceptionally low surface leakage current values, 10 to 100 times lower than those measured after our best wet passivation method for CZT surface chemical oxidation. Since AlO passivation significantly reduces surface leakage current and thus improves the signal-to-noise ratio, our finding is very promising for a substantial advancement of multi-stripe detectors performance.

Defects in cubic silicon carbide (3C-SiC) epilayers, that were grown using different techniques and on different substrates, were studied in terms of electrical activity and device limiting implications. An electrical characterization by conductive atomic force microscopy (C-AFM) showed that stacking faults (SFs) are normally the predominant type of defects that are electrically active at the semiconductor surface and, therefore, the most important defects that can affect the contact properties on these epilayers. It is also shown that an ultraviolet (UV) irradiation process can be used to suppress detrimental leakage currents passing through SFs that are carbon terminated at the semiconductor surface. Indeed, current-voltage characterization of Au/3C-SiC diodes showed a subsequent improvement of the Schottky behavior. (c) (2011) Trans Tech Publications.

Dark currents, including those in the surface and bulk, are the leading source of electronic noise in X-ray and gamma detectors, and are responsible for degrading a detector's energy resolution. The detector material itself determines the bulk leakage current; however, the surface leakage current is controllable by depositing appropriate passivation layers. In previous research, we demonstrated the effectiveness of surface passivation in CZT (CdZnTe) and CMT (CdMnTe) materials using ammonium sulfide and ammonium fluoride. In this research, we measured the effect of such passivation on the surface states of these materials, and on the performances of detectors made from them.

One of the most promising architectures of third generation solar cells is integration of single crystalline nanowires as electron transporters in anodes of electrochemical cells.[1-3] The nanowire-based cells aim at significantly increase cell efficiency thanks to the higher mobility of electrons along the single crystalline lattice of the nanowires with respect to traditional polycrystalline networks, greatly reducing electron-hole recombination controllable by passivation, functionalization or coaxial coating of the nanowire. The nanonetworks have been integrated in DSCs using the traditional N719 dye and the I-3/I-3 redox couple. The functional properties of the cells under 1 sun irradiation have been compared with traditional polycrystalline TiO2 photoanodes. ©2009 IEEE.

We studied the passivation effect of plasma deposited intrinsic and doped hydrogenated amorphous silicon layers on industrial grade, n-type, 1 ?cm multicrystalline silicon, aimed at the fabrication of Heterojunction (HJ) solar cells based on such material. The investigated variables include the process temperature, hydrogen dilution of silane during the intrinsic layer deposition, and passivating layer thickness. The structure of the passivating layers was analysed by optical measurements. Surface photovoltage and quasi-steady state photoconductance were used to characterize untreated and treated wafers. Thin a-Si:H layers exhibited the best passivating performance.