Study of Localized Levels in Semi-Insulators by Combined Measurements of Thermally Activated Ohmic and Space-Charge-Limited Conduction

Abstract

It is shown that measurement of thermal activation energies for both Ohmic and space-charge-limited conduction over a broad temperature range enables the deduction of both depth and concentration of localized levels in a semi-insulator, while measurement of the activation energy for Ohmic conduction alone is rarely definitive for a wide band-gap material. The basis for interpreting thermal activation energies for electrical conduction is discussed in detail. The analysis is applied to recent results on HgS, GaP, CdS, andZnS:Cd.

Electrical transport mechanisms and structure of hydrogenated and non-hydrogenated nanocrystalline Ga1−xMnxAs films

“…The constant h is defined as the ratio n/n t , being n the sum of the concentrations of free electrons thermally excited with excess electrons injected into the material, and n t the concentration of trapped electrons. The model proposed by Lampert and Mark [19][20][21][22] allows the estimation of the trap energy in the band gap (E t ) using the relationship…”

Influence of annealing on the surface semiconductive and photoconductive properties of nanostructured cadmium sulfide thin films

“…whereas for the simple case of single discrete trapping level, space charge-limited currents (SCLC) can be written as [41][42][43] …”

“…The cross over from ohmic to SCLC takes place at the voltage (V t ) given by other studies [41][42][43]:…”

Deep levels controlling the electrical properties of Fe-implanted GaInP∕GaAs

“…Furthermore, the electrical compensation induced by the balance of Fe-related deep acceptors and shallow donors is thermally stable, a great advantage with respect to compensation effects due to deep levels generated from defects introduced by the implantation process. To this aim, we have carried out current-voltage measurements at different temperatures ͑J-V-T͒ and employed the model developed by Schmidlin and Roberts,[8][9][10] which allowed for the determination of the location energy in the band gap of the deep levels that control the electrical properties of the Fe-implanted GaInP epilayers. 4,5 We have already reported 6 on the lattice damage evolution and Fe redistribution in lattice matched GaInP / GaAs epilayers after high temperature implantation and annealing.…”