High-resolution photoinduced transient spectroscopy as a new tool for quality assessment of semi-insulating GaAs

Broadening effects and ergodicity in deep level photothermal spectroscopy of defect states in semi-insulating GaAs: A combined temperature-, pulse-rate-, and time-domain study of defect state kinetics

“…Considering that there are many more levels in SI-GaAs besides the two apparent peaks, it is expected that the experimental spectrum reflects the superposition of several defect states. Since the defect states in SI-GaAs have already been well identified by other techniques, 34,35 more levels were included into our simulation. In view of the fact that the defect optical cross sections ͑ dla ͒ are not known in SI-GaAs, as a starting point they were assumed to be the same as the value shown in Table I.…”

“…The fitting parameters are summarized in Table II and the defects are identified according to the literature. 34,35 It should be noticed that parameters for HL3 and EL2 levels are determined from the phase spectra only, which will be discussed in detail later. Compared with the two-level theory, the superposition of more defect levels 9 gives considerably improved fits to the experimental spectrum in both amplitude and phase.…”

“…This variation in the defect characteristic temperature reflects the different probing principles of the two techniques. As pointed by Look, 42 for techniques monitoring the defect occupancy n T ͑t͒, such as in capacitance DLTS, 1 resonance occurs at e n = 2.36f, and for techniques monitoring the free carrier concentration n͑t͒, such as in photoinduced transient spectroscopy ͑PITS͒, 34 resonance occurs at e n = 6.35f. For this reason, the defect peak temperatures in n T ͑t͒-probing techniques are always higher than those of n͑t͒-probing techniques.…”

<title>Application of least-squares support vector machine (LS-SVM) to determination of deep level defect centers parameters in semi-insulating GaAs</title>

“…One of the useful techniques, which allow to investigate deep level defects parameters in semi-insulating semiconductors is Photoinduced Transient Spectroscopy (PITS) [6,7,8]. This method is based on measurement of the photocurrent excited by optical pulse falling on semiconductor sample.…”

Noncontact deep level photo-thermal spectroscopy: Technique and application to semi-insulating GaAs Wafers

“…3. 9 Several improvements of the theory have been introduced during the past few years, 11 but the theoretical transient still results in a simple exponential form unlike the experimental observations. Based on the energy levels characterized in PITS measurements, 8 E EL3 = 0.59 eV and EL3 =1ϫ 10 −13 cm 2 identify this peak as corresponding to the EL3 level.…”