Influence of deep level defects on carrier lifetime in CdZnTe:In

Abstract

The defect levels and carrier lifetime in CdZnTe:In crystal were characterized with photoluminescence, thermally stimulated current measurements, as well as contactless microwave photoconductivity decay (MWPCD) technique. An evaluation equation to extract the recombination lifetime and the reemission time from MWPCD signal is developed based on Hornbeck-Haynes trapping model. An excellent agreement between defect level distribution and carrier reemission time in MWPCD signal reveals the tail of the photoconductivity decay is controlled by the defect level reemission effect. Combining 241Am gamma ray radiation response measurement and laser beam induced transient current measurement, it predicted that defect level with the reemission time shorter than the collection time could lead to better charge collection efficiency of CdZnTe detector.

Determination of Defect Levels in Melt-Grown All-Inorganic Perovskite CsPbBr3 Crystals by Thermally Stimulated Current Spectra

“…Thermally stimulated current (TSC) technology is a simple and effective method for determining the defect levels in semiconductors with high resistivity . In this paper, the TSC technology was used to study the intrinsic point defect signatures in melt-grown semi-insulating CsPbBr 3 single crystals.…”

Degradation and device physics modeling of TiO2/CZTS ultrathin film photovoltaics

“…The application of this time-dependent method can be extended to other type of solar cells such as CdTe and CIGS devices [18], nanostructures [19], and other mechanisms [20] can be involved to make the simulations closer to reality. In a recent work [21], the role of different defect levels was investigated to show their impact on the electrical and optical properties of CZTS materials.…”

Temporal pulsed x-ray response of CdZnTe: In detector

“…It is well documented that defect levels are inevitable, which can significantly change the transient current waveform by trapping and recombination effects. [14] The multiple-trapping process [15] describes this dynamic of carriers restoring to equilibrium, as illustrated in Fig. 1(c).…”

“…For simplicity, only two trap levels, denoted as E nt and E pt , are considered for electrons and holes, respectively. In the CZT 127202-2 crystal grown under the Terich condition, the deep-level defect Te Cd with the second ionization energy of ∼ 0.59 eV and V Cd with the second ionization energy of ∼ 0.43 eV have been well known as the electron and hole trap centers, [14] respectively, which may dominate this relaxation process. Without considering the diffusion effect, the basic one-dimensional transportation equations for the free electron density n(x,t) and trapped charge density n t (x,t) in CZT crystal are as follows:…”

“…As the excess carriers in conduction band decay sufficiently, the trapped carriers will be thermally reemitted back into conduction band simultaneously, which dominates the slow component of the photo-response waveforms. [14] By the subsectional fitting of the transient current with single exponential, the fast decay time τ f and the slow decay time τ s are calculated to be 9.17 ns and 14.01 ns, respectively.…”