The transport simulations provided by the computer program AMPS have been used to give an in-depth analysis of role p-layer contact barrier height, mechanism, thickness, and quality on performance hydrogenated amorphous silicon p-i-n solar cells. We demonstrate for first time that, if height is below a critical value tunneling through not important, then cells with either active or dead p-layers varies regardless thickness. show even optimistic doping density 1019 cm−3, this high (∼1.2 eV)....

We have studied the current–voltage ( I – V ) characteristics of p + a-SiC:H/n c-Si heterojunction solar cells at different conditions. Under standard test conditions (300 K, 100 mW/cm 2 , AM1.5) these show normal with a high fill factor (FF = 0.73) and relatively efficiency for their simple structure (η≈13%). However, below room temperature illumination levels above 10 they exhibit an S-shaped curve low factor. Simulation studies revealed that this effect is caused by valence band...

The distribution of the A-center (oxygen vacancy) in neutron-damaged silicon detectors was studied using deep level transient spectroscopy. A-centers were found to be nearly uniformly distributed wafer depth for medium-resistivity (0.1-0.2-k Omega -cm) and high-resistivity (>4-k high-temperature (1200 degrees C) oxidized detectors. A positive filling pulse needed detect detectors, this effect dependent on oxidation temperature. not observed a sample from with TCA having very high carbon...

A wide band gap heterolayer is usually added to the front face of GaAs and other III–V solar cells favour transparency passivate emitter. This extra layer influences optical behaviour device therefore must be taken into account in optimization antireflection (AR) coating. set AR layers was optimized with respect their thicknesses for an InGaP cells. Complementary, numerical simulation whole performed using D-AMPS code. Our results confirm importance surface passivation demonstrate that...

The kinetics controlling the electrical transport inside μc-Si tunnel-recombination junction (TRJ) of a-Si:H/a-Si:H tandem solar cells was studied in detail with computer simulations. Trap assisted recombination tunneling and Poole–Frenkel mechanisms were included our analysis. Three different tunnel junctions investigated: (a) n-p, (b) n-oxide-p (c) n-i-p. highest theoretical efficiencies achieved n-i-p structure. impact effective masses, mobility gap, mobilities cell efficiency is also...

We have studied by Raman spectroscopy and electro-optical characterization the properties of thin boron doped microcrystalline silicon layers deposited plasma enhanced chemical vapor deposition (PECVD) on crystalline wafers amorphous buffer layers. Thin 20–30 nm p+ μc-Si:H with a considerably large volume fraction (∼22%) good window were under moderate PECVD conditions. The performance heterojunction solar cells incorporating such critically dependent interface quality type layer used. A...

We used the internal photoemission (IPE) technique to accurately determine valence and conduction band offsets at a-SiC:H/c-Si interface investigated with numerical simulations their effects on photocarrier collection in p+ a-SiC:H/n c-Si heterojunction solar cells. The discontinuities were found be 0.60 0.55 eV, respectively. However, despite large barrier edge, 30 nm cells show no problems due blocking of holes (FF=0.73). Combined IPE measurements simulation results indicate that tunneling...

The transport-simulation computer program amps has been used to examine the role of contact barrier heights in determining performance a-Si:H p-i-n homojunction detector and solar-cell devices. Current-voltage performance, with without illumination present, is considered. It determined that for p n layers are sufficiently thick doped, reverse bias currents, both dark under illumination, do not depend or only weakly on contacts doped layers. However, these can strongly influence illuminated...

The transport mechanisms controlling the forward dark current-voltage characteristic of silicon micromorph tandem solar cell were investigated with numerical modeling techniques. characteristics structure at voltages show three regions: two an exponential dependence and a third where current grows more slowly applied voltage. In first region is entirely controlled by recombination through gap states top cell. second mixture both bottom cells free carrier diffusion along a-Si:H intrinsic...

The performance of hydrogenated amorphous silicon (a-Si:H) p-i-n solar cells is limited, as they contain a relatively high concentration defects. dark current voltage (JV) characteristics at low forward voltages these devices are dominated by recombination processes. rate depends on the active centers and efficacy each centers. first factor causes ideality to be non-integer vary with voltage. temperature dependence can expressed its activation energy. For microcrystalline energy varies...

The implementation of trap-assisted tunneling charge carriers into numerical simulators ASPIN and D-AMPS is briefly described. Important modeling details are highlighted compared. In spite the considerable differences in both approaches, problems encountered their solutions surprisingly similar. Simulation results obtained for several recombination junctions made amorphous silicon (a-Si), carbide (a-SiC), or microcrystalline (μc-Si) analyzed. Identical conclusions can be drawn using either...

Experimental results of very large, long-wavelength photocurrent gains in amorphous silicon-based Schottky barrier structures are reported. It is shown that these occur for devices the space-charge current regime operated at forward bias voltages past flatband condition. The analysis microelectronic and photonic computer program used to show high due hole trapping resulting modulation virtual cathode potential ohmic contact. As demonstrated, voltage, light, monochromatic light intensity,...

In this article we discuss basic aspects of single junction a-SiGe:H p–i–n solar cells by coupling computer simulations with experimental characteristics. We are able to fit the dark illuminated current–voltage characteristics and spectral response curves structures in initial state, modeling density dangling bonds each device layer using either uniform profiles or defect pool model. Although can these any two electrical models, band gap profiling intrinsic leads improvement cell performance...

We present experimental and modeling results for the subgap absorption coefficient of intrinsic doped hydrogenated amorphous silicon (a-Si:H) in order to explore limitations constant photocurrent method (CPM). To properly model coefficient, we have developed a simulation computer program including all possible optical thermal transitions between gap extended states. Tail states are assumed be either donor- or acceptorlike midgap amphoteric. The defect-pool is also incorporated our analysis....

The device physics behind hole direct tunneling currents at the front contact of a-Si:H p-i-n homojunction have been explored. In this paper, dark I-V, light and QE characteristics structure with without are evaluated compared. three differential equation systems Poisson's equation, continuity for free electrons, holes solved allowances currents. Hole homojunctions give rise to a significant increase in current level high forward voltages an open-circuit voltage I-V characteristic when...

The performance of a-Si:H devices is highly sensitive to the density gap states: tail states are distributed in two exponentials and defect generated by dangling bonds (DB). DB can be evaluated with pool model (DPM). Charge trapping recombination electron–hole pairs through described Shockley–Read–Hall (SRH) formalism while behave as amphoteric. Equations derived SRH simplified Simmons–Taylor's approximation (STA), especially “0 K” (0KSTA). Amphoteric-like were approximated donor-...