Observation of temperature-dependent capture cross section for main deep-levels in β-Ga2O3

Direct observation of the capture cross section is challenging due to the need for extremely short filling pulses in the two-gate Deep-Level Transient Spectroscopy (DLTS). Simple estimation of the cross section can be done from DLTS and admittance spectroscopy data but it is not feasible to distinguish temperature dependence of pre-exponential and exponential parts of the emission rate equation with sufficient precision conducting a single experiment. This paper presents experimental data of deep levels in β-Ga2O3 that has been gathered by our group since 2017. Based on the gathered data, we propose a derivation of apparent activation energy ( E a m ) and capture cross section ( σ n m ) assuming the temperature dependent capture via the multiphonon emission model, which resulted in a strong correlation between E a m and σ n m according to the Meyer–Neldel rule, which allowed us to estimate low- and high-temperature capture coefficients C 0 and C 1 as well as capture barrier E b. It also has been shown that without considering the temperature dependence of capture cross section, the experimental values of σ n are overestimated by 1–3 orders of magnitude. A careful consideration of the data also allows to be more certain identifying deep levels by their “fingerprints” ( E a and σ n) considering two additional parameters ( E M N and σ 00) and to verify the density functional theory computation of deep-level recombination properties.