Alternative Way for Detecting Franck‐Condon Shifts from Thermally Broadened Photoneutralization Cross‐Section Bands of Deep Traps in Semiconductors

Photoionization cross-section analysis for a deep trap contributing to current collapse in GaN field-effect transistors

“…5,26,29,42,46,49,53 The latter is seen to be shifted from the associated thermal ionization energy, E T ͓ϭelectronic absorption edge; cf. 5,26,29,42,46,49,53 The latter is seen to be shifted from the associated thermal ionization energy, E T ͓ϭelectronic absorption edge; cf.…”

Correlation of electrical and optical properties of the vanadium-related C level in silicon

“…4,5 By connecting optical level positions with Gibb's free energies derived directly ͑i.e., without any intermediate exponential regression procedures 2,6 ͒ from ratios of thermal hole emission rates and capture coefficients, we were further able to determine all parameters necessary for a numerical analysis of the temperature dependence of the zero-phonon binding energy, J p (T), Gibb's free energy, G p (T), and the associated enthalpy, H p (T), over an unusually large temperature range ͑0рTр300 K͒. Furthermore, the extension of our photoionization cross-section measurements to rather low photon energies made it possible to present a reliable estimation of the lattice adjustment energy 7,8 ͑ϭFranck-Condon shift 9 ͒ for the vanadium-related C level in silicon. This energy is shown to be a factor of about 3 smaller than the one suggested by Ohta and Sakata 10 on the basis of a numerical analysis of their thermal capture and emission data.…”

Alternative electronic parts for multiphonon-broadened photoionization cross sections of deep levels in SiC

“…where D is the Franck-Condon shift ͑i.e., the center of gravity of the FC factor curve͒ and M ͑2͒ ͑T͒ the associated second moment with respect to D. ͑Note that, within the commonly considered regime of linear interaction of the electronic subsystem with harmonic vibrational modes, [31][32][33]50,51,[60][61][62][63][64][65]89,[91][92][93] the FC shift is independent of T.͒ Using, henceforth, for the FC factor, R͑h − E e , T͒ in Eq. ͑1͒, the semiclassical ͑Gaussian-type͒ approximation ͑2͒ ͑where ⌬E = h − E e ͒, we reduce the original expression ͑1͒ to an approximate ͑semiclassical͒ version,…”

“…Assessments of capture data for deep traps in group IV, III-V, and II-VI materials have shown that, for sufficiently low temperature, the nonradiative cascade capture mechanism 26,27,30,36,40 generally dominates at attractive centers, whereas the radiative capture mechanism 26,[28][29][30]32,37,38,41 is predominant at many neutral centers below room temperature ͑provided their coupling to the lattice is relatively weak 32,37,38 ͒. ͑Note that the FC shift has been denoted in earlier papers alternatively by ⌬, 49 ⌬ FC , 50,51 d FC , 48,[52][53][54][55][56][57][58][59] A, [42][43][44][45][46][60][61][62][63][64][65] or S [31][32][33] .͒ Thus it is of primary importance to get quantitative information on this crucial trap parameter if we want to come to a better understanding of the electrical properties of deep levels. 26,34,37,38,[42][43]…”

“…is to analyze experimental data sets of thermally activated ͑T-dependent͒ photoionization or photoneutralization crosssection spectra, [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] ͑h , T͒, that are due to optical excitation of electrons or holes from the deep-trap level into the conduction or valence band, respectively. For deep traps in SiC, some ͑h , T͒ spectra have been measured by various conventional experimental techniques such as optical absorption, [69][70][71] photocapacitance, [72][73][74] and photoconductivity 75 measurements, or by the more recently developed optical-capacitance-transient spectroscopy ͑O-CTS͒ method.…”