【International Papers】Observation of temperature-dependent capture cross section for main deep-levels in β-Ga₂O₃

      Researchers from the National University of Science and Technology MISIS have published a dissertation titled " Observation of temperature-dependent capture cross section for main deep-levels in β-Ga₂O₃" in Journal of Applied Physiology.

Abstract

      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 C₀ and C₁ 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 σn 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_MN and σ_00⁠) and to verify the density functional theory computation of deep-level recombination properties.

FIG. Configurational diagram. E_d—energy of electron on a defect with Q = Q_d (non-equal to 0 with the presence of electron–lattice interaction) and E_k—excited state that is delocalized and since then Q = 0 (small electron–lattice coupling to local mode Q).

DOI：

https://doi.org/10.1063/5.0209322