Articles you may be interested inOptical gain at 1.54 μm in erbium-doped silicon nanocluster sensitized waveguide Appl. Phys. Lett. 79, 4568 (2001); 10.1063/1.1419035Deposition and 1.54 μm Er 3+ luminescent properties of erbium-doped hydrogenated amorphous silicon thin films by electron cyclotron resonance plasma enhanced chemical vapor deposition of SiH 4 with concurrent sputtering of erbium Assessment of as-deposited microcrystalline silicon films on polymer substrates using electron cyclotron resonance-plasma enhanced chemical vapor deposition

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Interface trap densities at gate oxide/silicon substrate (SiO2/Si) interfaces of metal oxide semiconductor field-effect transistors (MOSFETs) were determined measuring the substrate bias dependence of the subthreshold slope. This method enables the characterization of interface traps residing between the midgap and strong inversion (2 times the Fermi potential) of small MOSFETs. In consequence of the high accuracy of this method, the energy dependence of the interface trap density is more reliable. The application of this technique to a MOSFET showed good agreement with the result obtained through the high-frequency/quasi-static capacitance-voltage (C-V) technique for a MOS capacitor. Furthermore, substrate dopant concentration obtained as a by-product through this technique also showed good agreement with the result obtained through the body effect measurement.

We have analyzed low temperature (12 K) photoluminescence (PL) characteristics of carbon(C) doped GaAs epilayers. No traces of donor levels were observed in the PL spectra. This suggest that well-behaved carbon is incorporated as an acceptor into the GaAs lattice. The measured peak energy of the PL intensity distribution shifts to lower energy and the full width at half maximum (FWHM) increases with increasing hole concentration. We have obtained empirical relations for FWHM of PL intensity distribution in two distinct hole concentration regions. These relations are considered to provide a useful tool to determine free hole concentration in C doped GaAs by low temperature PL measurements. As the hole concentration is increased above 2×1019 cm−3, a shoulder separated from the PL peak was observed in the PL spectra at Eg+EF, where  Eg is the band gap and EF is the Fermi energy. The shoulder became very prominent at 9.2×1019 cm−3.

We propose a simulation model to explain two-dimensional field-effect operation of undoped poly-Si thin-film transistors (TFTs) under small drain voltages. Our model includes both thermionic-emission and drift-diffusion conduction processes. We calculated grain-boundary potential barriers, channel currents, and various device parameters depending on grain size and defect density. In order to validate our model, we compared calculated currents with experimental data for two types of poly-Si TFTs. We could obtain good current fits simultaneously in both subthreshold and linear regions by adopting proper densities of states in the poly-Si channels. We could also explain well the temperature-dependent current changes and the current activation energy versus the gate voltage. Finally, we succeeded in modeling the drain current under small drain voltages by using the combined transport process in the two-dimensional grain-boundary structure.