A. N. Kuznetsov

Room‐temperature photoluminescence of erbium‐doped hydrogenated amorphous silicon

A comparison of the photoluminescence of Er‐doped hydrogenated amorphous silicon and crystalline silicon a‐Si:H(Er) and c‐Si(Er), is presented. It is shown that a‐Si:H(Er) exhibits efficient room‐temperature photoluminescence at 1.537 μm which is as strong as the emission from optimized c‐Si(Er) at 2 K. Most remarkably, there is practically no temperature quenching of the emission intensity in the range 2–300 K. The experiments suggest that the lifetime connected with the Er‐induced emission is considerably shorter in a‐Si:H(Er) than in c‐Si(Er) which may be responsible for the different dependences of the photoluminescence intensity on the temperature, chopping frequency, and excitation power.

Local environment of erbium atoms in amorphous hydrogenated silicon

The 169Er(169Tm)emission Mossbauer spectroscopy has evidenced that photoluminescence centers in Er-doped amorphous hydrogenated silicon are [Er–O] clusters. The local environment of the Er3+ ions in the clusters is similar to the Er3+ environment in Er2O3.

Room-temperature electroluminescence of erbium-doped amorphous hydrogenated silicon

We have observed strong room-temperature electroluminescence at 1.54 μm induced by erbium ions in amorphous hydrogenated silicon (a-Si:H). The device consisted of an Al/a-Si:H(Er)/n-c-Si/Al structure. A mechanism for electronic excitation of the erbium ions in the amorphous matrix is proposed that is based on defect-related Auger excitation.

Electrical characteristics of p-3C-SiC/n-6H-SiC heterojunctions grown by sublimation epitaxy on 6H-SiC substrates

Abstract Sublimation epitaxy in a vacuum (SEV) has been used to obtain p-3C–SiC/n-6H–SiC heteroepitaxial structures. Results of a study of epilayers (X-ray diffraction analysis, scanning electron microscopy involving secondary electrons and electron beam induced current modes) and diode structures on their base ( I – V and C – V characteristics, electroluminescence spectra, DLTS) are presented. Band discontinuities are determined and a band diagram of the p-3C–SiC/n-6H–SiC heterostructure is constructed.

Amplification of the signal in triode structures of ion detectors based on 6H-SIC epitaxial films

The possibility of about 50 times the inneramplification of signals in SiC-based detectors of short-range ions is shown. The detector has an n–p–n+-like structure, where the p-type base was grown epitaxially on a 6H n+-SiC substrate. To complete the structure a Schottky barrier was made on top. Detector parameters were investigated in a “floating base” regime. Alpha particles from 244Cm were used and the augmentation of signal (E) with increasing applied voltage (U) was investigated. A superlinear increase of E was observed with a significant (tens of times) amplification of the introduced by the alpha particle nonequilibrium charge. It was also found that the nonuniformity of the diffusion-drift carrier transport parameters in the films does not exceed 10%.

Room-Temperature Photoluminescence of Amorphous Hydrogenated Silicon Carbide Doped With Erbium

Recently the luminescent properties of erbium-doped crystalline silicon (c-Si:Er) have attracted much attention. The reason for this interest originates from the idea to fabricate LED’s which are integrable into silicon electronic devices and emit at a wavelength of 1,537 μm where the absorption of silica glass optical fiber is the lowest. The photoluminescence (PL) of c-Si:Er is strongly quenched with increasing temperature.

Room-temperature electroluminescence of Er-doped hydrogenated amorphous silicon

Abstract We have observed room-temperature erbium-ion electroluminescence in erbium-doped amorphous silicon. Electrical conduction through the structure is controlled by thermally activated ionization of deep D − defects in an electric field and the reverse process of capture of mobile electrons by D 0 states. Defect-related Auger excitation (DRAE) is responsible for excitation of erbium ions located close to dangling-bond defects. Our experimental data are consistent with the mechanisms proposed.

Study of the properties of a two-dimensional electron gas in p−-3C-SiC/n+-6H-SiC heterostructures at low temperatures

The photoluminescence and magnetoresistance spectra of p−-3C-SiC/n+-6H-SiC heterostructures are studied at temperatures ranging from 6 to 80 K. These studies show that the heterojunction affects both the photoluminescence spectrum and the magnetoresistance. However, the rather poor structural quality of the epitaxial structures has so far prevented the classical effects for structures with a two-dimensional electron gas from being observed. Presumably, a refinement of the experimental technique and, also, optimization of the growth and postgrowth technologies for SiC will make it possible to observe these effects in the near future.

Semi-insulating silicon carbide layers obtained by diffusion of vanadium into porous 4H-SiC

Semi-insulating silicon carbide layers have been obtained by diffusion of vanadium into porous 4H-SiC. The diffusion was performed from a film deposited by cosputtering of silicon and vanadium, with the content of the latter equal to 20%. The diffusion profile of vanadium in porous silicon carbide has a complex structure with a fast diffusion coefficient of 7×10−15 cm2/s. The activation energy of the resistivity of vanadium-diffusion-doped porous SiC layers is 1.45 eV. The resistivity of vanadium-doped semi-insulating layers is 5×1011 Ω cm at 500 K, which exceeds the resistivity of undoped porous SiC by two orders of magnitude. The results obtained indicate that porous SiC is a promising material for semi-insulating substrates in device structures based on wide-bandgap semiconductors.

3C-SiC p-n structures grown by sublimation on 6H-SiC substrates

Sublimation epitaxy in a vacuum has been employed to grow n-and p-type 3C-SiC layers on 6H-SiC substrates. Diodes have been fabricated on the basis of the p-n structure obtained, and their parameters have been studied by measuring their current-voltage and capacitance-voltage characteristics and by applying the DLTS and electroluminescence methods. It is shown that the characteristics of the diodes studied are close to those of diodes based on bulk 3C-SiC. A conclusion is made that sublimation epitaxy can be used to fabricate 3C-SiC p-n structures on substrates of other silicon carbide polytypes.