Volume 92, Issue 6, 15 September 2002
Index of content:
Electron emission from deep level defects EL2 and EL6 in semi-insulating GaAs observed by positron drift velocity transient measurements92(2002); http://dx.doi.org/10.1063/1.1503162View Description Hide Description
A ±100 V square wave applied to a Au/semi-insulating SI–GaAs interface was used to bring about electron emission from and capture into deep level defects in the region adjacent to the interface. The electric field transient resulting from deep level emission was studied by monitoring the positron drift velocity in the region. A deep level transient spectrum was obtained by computing the trap emission rate as a function of temperature and two peaks corresponding to EL2 eV) and EL6 eV) have been identified.
Formation of carbonized porous silicon surfaces by thermal and optically induced reaction with acetylene92(2002); http://dx.doi.org/10.1063/1.1497464View Description Hide Description
Formation of a carbonized porous silicon surface by thermal and photo-assisted reaction with gas phase acetylene is reported. The porous silicon samples subjected to flowing acetylene either in a heated quartz reactor or under optical illumination show strong quenching of the photo- luminescence(PL) followed by a recovery on further exposure to acetylene. In thermally treated samples, a significant blue shift of 80 nm was observed. The recovered PL signal does not exhibit quenching on further exposure to laser illumination.Fourier transform infrared spectroscopy investigations confirm absence of absorption and no enhancement of the oxygen back bonded Si–H bonding. It indicates the formation of a practically stable carbonized porous silicon surface.