Composition related electrical active defect states of InGaAs and GaAsN

This paper discusses results of electrically active defect states - deep energy level analysis in InGaAs and GaAsN undoped semiconductor structures grown for solar cell applications. Main attention is focused on composition and growth condition dependent impurities and the investigation of their possible origins. For this purpose a widely utilized spectroscopy method, Deep Level Transient Fourier Spectroscopy, was utilized. The most significant responses of each sample labelled as InG2, InG3 and NG1, NG2 were discussed in detail and confirmed by simulations and literature data. The presence of a possible dual conduction type and dual state defect complex, dependent on the In/N composition, is reported. Beneficial characteristics of specific indium and nitrogen concentrations capable of eliminating or reducing certain point defects and dislocations are stated

Numerical Approach to the Problem of Digital DLTS Measurements Signal analysis

This paper presents a novel approach in the investigation of the parameters of deep energy levels in digital DLTS (Deep Level Transient Spectroscopy) measurements. A DLTS spectra fitting algorithm and by this the calculation of the activation energy capture cross section and the trap concentration of deep energy levels is proposed. As a final result the match between fitted and evaluated parameters are presented. The fitted curves are used as representatives for a peak in the DLTS spectra. The measured DLTS signals were used for the results comparison of the numerical fitting approach and the standard DLTS direct evaluation method