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In recent years, research attention has increasingly focused on thin-film photovoltaics utilizing Sb2Se3 as an ideal absorber layer. This compound is favored due to its abundance, non-toxic nature, long-term stability, and the potential to employ various cost-effective and scalable vapor deposition (PVD) routes. On the other hand, improving passivation, surface treatment and p-type carrier concentration is essential for developing high-performance and commercially viable Sb2Se3 solar cells. In this study, Cu-doped Sb2Se3 solar devices were fabricated using two distinct PVD techniques, pulsed electron deposition (PED) and radio frequency magnetron sputtering (RFMS). Furthermore, 5%Cu:Sb2Se3 films grown via PED exhibited high open-circuit voltages (VOC) of around 400 mV but very low short-circuit current densities (JSC). Conversely, RFMS-grown Sb2Se3 films resulted in low VOC values of around 300 mV and higher JSC. To enhance the photocurrent, we employed strategies involving a thin NaF layer to introduce controlled local doping at the back interface and a bilayer p-doped region grown sequentially using PED and RFMS. The optimized Sb2Se3 bilayer solar cell achieved a maximum efficiency of 5.25%. [ABSTRACT FROM AUTHOR]

Copper-doped antimony selenide (Cu-doped Sb2Se3) thin films were deposited as absorber layers in photovoltaic solar cells using the low-temperature pulsed electron deposition (LT-PED) technique, starting from Sb2Se3 targets where part of the Sb was replaced with Cu. From a crystalline point of view, the best results were achieved for thin films with about Sb1.75Cu0.25Se3 composition. In order to compare the results with those previously obtained on undoped thin films, Cu-doped Sb2Se3 films were deposited both on Mo- and Fluorine-doped Tin Oxide (FTO) substrates, which have different influences on the film crystallization and grain orientation. From the current-voltage analysis it was determined that the introduction of Cu in the Sb2Se3 absorber enhanced the open circuit voltage (VOC) up to remarkable values higher than 500 mV, while the free carrier density became two orders of magnitude higher than in pure Sb2Se3-based solar cells. [ABSTRACT FROM AUTHOR]

Research was conducted to examine the electrical characteristics of terbium ions in crystalline Si elucidating the role played by defects, thermal annealing and oxygen content in the dissociation and formation of Tb-related complexes. The Si junctions were implanted with 5 MeV Tb ions while some epitaxial Si samples were coimplanted with O. Annealing was performed at temperatures ranging from 800 to 1000 degrees C. Results indicate that O diffusion to Tb ions at approximately 900 degrees C generated the growth and dissolution kinetics of Tb-O complexes.

The realization of low resistivity and stable contacts on p-type CdTe is still challenging, especially if high annealing temperatures must be avoided. In this paper, the electrical characteristics of [Sb.sub.2] [Te.sub.3] contacts on p-type CdTe single crystals are studied. It is found that the resistivity of the contacts is low and constant with time.

Vertical transport in p-i-n diodes containing InGaP/GaAs multi-quantum-wells (MQW) is investigated using current-voltage measurements under forward bias at different temperatures. At low injection, the experimental data are analyzed through a two diode model, by taking into account the non-complete depletion of the MQW region caused by unintentional p-type doping. The diffusion current results to be dominant at high temperatures, whereas the current due to non-radiative recombination through defects in the space charge region becomes more and more relevant as the temperature is reduced. At temperatures above T = 150 K and at high forward voltages, when the current is limited by the series resistance, the thermionic emission of holes over the InGaP barriers controls the transport through the whole MQW region. At lower temperatures resonant tunneling of holes takes place and a simple picture of the hole quantum levels permits to interpret the main details of the I(V) curves at T = 41 K, by supporting the hypothesis of a uniform electric field in the MQW region up to about 100 kV/cm. [ABSTRACT FROM AUTHOR]

Photoelectrical measurements were taken on a nominally undoped-InGaP/GaAs superlattice, inserted between two p+ and n+ InGaP cladding layers. The sequence of InGaP/GaAs alternated layers forming the superlattice was grown lattice matched on n+-GaAs substrates through low pressure-metal organic vapor phase epitaxy, at growth conditions previously optimized for obtaining sharp interfaces and negligible ordering effects in the cation sublattice of the InGaP layers. A peculiar dependence of both the photocurrent and the photovoltaic signals on the modulation frequency of the exciting light beam was observed and then interpreted according to proper equivalent electrical circuits. The effects induced by an incomplete depletion of the nominally undoped superlattice region are analyzed in detail, and the analogies between photoelectrical investigation and admittance spectroscopy are pointed out. [ABSTRACT FROM AUTHOR]

Examines a hole diffusion length in liquid-encapsulated-Czochralski GaAs monocrystals, using photon and electron bombardment through semitransparent gold and chromium Schottky electrodes. Relationship of the diffusion length investigation carried out by the steady-state surface photovoltage and the scanning electron microscope electron-beam-induced current with the spectral quantum efficiency of Schottky diodes; Methods used to determine the diffusion length L and its equivalent parameter.

The quest for single-stage deposition of CuInGaSe2 (CIGS) is an open race to replace very effective but capital intensive thin film solar cell manufacturing processes like multiple-stage coevaporation or sputtering combined with high pressure selenisation treatments. In this paper the most recent achievements of Low Temperature Pulsed Electron Deposition (LTPED), a novel single stage deposition process by which CIGS can be deposited at 250 °C, are presented and discussed. We show that selenium loss during the film deposition is not a problem with LTPED as good crystalline films are formed very close to the melting temperature of selenium. The mechanism of formation of good ohmic contacts between CIGS and Mo in the absence of any MoSe2 transition layers is also illustrated, followed by a brief summary of the measured characteristics of test solar cells grown by LTPED. The 17% efficiency target achieved by lab-scale CIGS devices without bandgap modulation, antireflection coating or K-doping is considered to be a crucial milestone along the path to the industrial scale-up of LTPED. The paper ends with a brief review of the open scientific and technological issues related to the scale-up and the possible future applications of the new technology. [ABSTRACT FROM AUTHOR]

The realization of low resistivity and stable contacts on p-type CdTe is still challenging, especially if high annealing temperatures must be avoided. In this paper, the electrical characteristics of Sb2Te3 contacts on p-type CdTe single crystals are studied. It is found that the resistivity of the contacts is low and constant with time. [ABSTRACT FROM AUTHOR]

A great interest is devoted to the development of memories having both high density and low energy consumption for application in personal computers and in automated electronic devices. This target can be achieved if a high dielectric material is obtained. One of the most promising candidates is aluminium oxide, Al2O3, due to its high dielectric constant (∼10), wide band gap (∼8 eV) and thermal stability. Al2O3 can be prepared as an amorphous layer, consequently avoiding strain and electrically active states at the interface between the oxide and the substrate material. In this communication we report on the growth of amorphous Al2O3 layers on n-type silicon. [ABSTRACT FROM AUTHOR]