Deep-level spectroscopy in high-resistivity materials

Abstract

A simple method to characterize deep levels in high-resistivity materials is described. Excess carriers are optically injected by pulsed light. The detrapping of these carriers leads to a transient current collected between two contacts. The signal is analyzed as in DLTS, i.e., deep level spectra are recorded during temperature cycles. Some examples of the use of this method are given.

Tutorial: Junction spectroscopy techniques and deep-level defects in semiconductors

“…Light is directed between the contacts or through the Schottky barrier. The technique was first proposed by Hurtes et al 56 to study high resistivity GaAs and has since been elaborated by many other groups for use on a range of materials. Usually above band gap light is used but in some cases the occupancy can be perturbed by sub-band gap irradiation.…”

Cathodoluminescence and photoinduced current spectroscopy studies of defects inCd0.8Zn0.2Castaldini1, Cavallini2, Fraboni3 et al. 1996Phys. Rev. B403170View full textAdd to dashboardCite

“…Only a few results on investigations of deep levels in Cd 1Ϫx Zn x Te have appeared so far in the literature, and a better understanding of their properties and nature is needed Capacitance junction spectroscopy cannot be used to investigate semi-insulating materials, which require dedicated spectroscopies such as photoinduced current transient spectroscopy ͑PICTS͒. 2,3 The PICTS method has the special feature of detecting traps which may lay quite deep in the forbidden gap, a characteristic which other commonly used techniques ͑e.g., thermally stimulated current͒ do not possess. In addition, luminescence techniques are suitable to investigate the electronic properties of defects in this ternary compound.…”

Deep‐level transient conductance spectroscopy of high resistivity semiconductors

“…This difficulty can be overcome using optical transient-conduction spectroscopy (OTCS) as described by Hurles et al [2] for the detection of deep-level trapping centres in GaAs, and further applied by Yuba et al [3,4] to both GaAs and InP. Essentially the technique involves the periodic filling of trapping centres by carriers generated by the pulsed laser light followed by rate analysis of the exponentially decaying, thermally stimulated, trap-emptying transient currents as the sample temperature is slowly ramped.…”