Transient space charge limited current spectroscopy method of measuring the position and concentration of trap levels in semi‐insulating materials

A new method is reported to measure the position and concentration of trap levels in semi‐insulating materials where the regular deep level transient spectroscopy method is not applicable. In the proposed method, a transient space charge limited current (TSCLC) associated with the trap levels is measured using a capacitance balanced square wave voltage source, a voltage limiter‐amplifier and a double box car averager. The TSCLC method is demonstrated on a p‐type Y_2.01Ca_0.99Ge_0.91Fe_4.09O₁₂ magnetic garnet sample ρ₃₀₀=10⁷ Ω cm. The trap level is located at 0.36 eV above the valence band edge and the concentration of the trapped holes is found to be 10¹³–10¹⁵ cm⁻³.