Amorphous silicon

About: Amorphous silicon is a research topic. Over the lifetime, 26777 publications have been published within this topic receiving 423234 citations.

On-chip parametric amplification with 26.5 dB gain at telecommunication wavelengths using CMOS-compatible hydrogenated amorphous silicon waveguides

Abstract: We present what we believe to be the first study of parametric amplification in hydrogenated amorphous silicon waveguides. Broadband on/off amplification up to 26.5 dB at telecom wavelength is reported. Measured nonlinear parameter is 770 W−1 m−1, nonlinear absorption 28 W−1 m−1, bandgap 1.61 eV.

Photoluminescence quantum yields of amorphous and crystalline silicon nanoparticles

Abstract: While nanocrystalline silicon is known to be an efficient optical emitter, there have been few and sometimes contradictory reports of emission from amorphous silicon nanoparticles. This paper presents a study of the optical properties of amorphous and crystalline silicon nanoparticles synthesized by a nonthermal plasma reactor. By tuning the power delivered to the reactor, the particle structure was adjusted from amorphous to crystalline without otherwise changing the particle properties, such as nanoparticle size, in a significant manner. Two different kinds of surface passivation of nanoparticles are studied: the surface functionalization with organic ligands in a scheme known as hydrosilylation and the passivation with a native surface oxide. We observe a clear trend of the photoluminescence quantum yield increasing with the increasing degree of crystallinity of samples with largely amorphous samples, exhibiting almost no luminescence. Measurements suggest that the upper bound for the quantum yield of amorphous nanoparticles is 2%, while the quantum yield of silicon nanocrystals is routinely found to exceed 40%.

Thermal generation currents in hydrogenated amorphous silicon p - i - n structures

Abstract: Dark conductivity in amorphous silicon p‐i‐n devices arising from thermal generation through bulk defect states is explored. The current decays slowly after a voltage is applied, due to depletion of charge from the undoped layer, and is voltage dependent due to a field‐enhanced generation rate. Creation of metastable bulk defects by light soaking reversibly increases the current. The steady‐state generation current is dervied from the measured relaxation time and depletion charge.

Aluminum-induced crystallization of amorphous silicon

Abstract: We investigated the aluminum-induced crystallization of amorphous silicon (a-Si) during the aluminum-induced layer exchange (ALILE) process, in which a stack of glass/Al/a-Si is transformed into a glass/polycrystalline silicon (poly-Si)/Al(Si) structure by an annealing step well below the eutectic temperature of the Al/Si system. Our experiments resulted in continuous large-grained poly-Si films on glass substrates. The nucleation and the growth of the crystalline phase during the ALILE process was observed using an optical microscope. We found an activation energy of 1.8 eV for the nucleation process and we related this energy to a large barrier at the a-Si/Al interface.