Shallow Energy States in CdTe

Abstract

The energetic positions Et of the shallow states for variously prepared CdTe (110) surface are determined, basing on results of surface photovoltage spectroscopy(SPS) measurements in the temperature range between 80 and 300 K. The measurements are performed with the Kelvin method using a modified measuring system.

Surface Photovoltage Spectroscopy of Cd0.97Fe0.03Se and Cd0.97Fe0.03Te Crystals

“…1b). This transition is clearly visible for different temperatures, and was observed in pure CdTe spectum reported in many papers [9,10].…”

Surface photovoltage phenomena: theory, experiment, and applications

“…Lassabatere et al [329] suggested to use the maximum of the derivative of the SPV signal with respect to the photon wavelength as indicative of the bandgap, and obtained results of the temperature dependence of the GaAs bandgap which were in very good agreement with the literature. This approach has also been used by Kuzminski and Szaynok [387]. Fig.…”

“…This is not coincidental, as gap states associated with the band with which they communicate typically feature the same dependence as the bandgap energy on the bandgap-modulating parameter. Using this idea in a systematic manner, a correlation between gap states and bands was found in CdTe [387] and CdMnTe [388] via temperature-induced bandgap changes, and in InAlAs thin ®lms [355] via alloy-composition-induced bandgap changes. In the latter case, other groups of gap states whose energy position was clearly not associated with any band were also found.…”

Reduction of Fermi level pinning and recombination at polycrystalline CdTe surfaces by laser irradiation

“…This has been successfully modeled in a similar CdTe device structure by the inclusion of a surface space charge region 14 and confirmed by its elimination due to various surface treatments. 15,18 The disappearance of this feature in the LT material (the signal remains of the same sign above 1.5 eV) is evidence that surface defects have been removed or passivated. This corresponds to the scenario in Fig.…”