Spectral Analysis of Deep Level Transient Spectroscopy (SADLTS) of DX-centers in AlxGa1-xAs:Sn

Emission rate spectra S(λ, T) of DX-centers in AlxGa1-xAs:Sn for x=0.35, 0.45, 0.55, 0.65 and 0.75 were obtained from the transient capacitance waveform ΔC(t, T) by the spectral analysis proposed in our previous paper. S(λ, T)'s were distributed over the range λ∼10∼103 between 170∼200 K and showed double peak features for x=0.35, 0.45 and 0.55. S(λ, T)'s broaden, shift to higher λ and decrease their peak heights at higher temperatures. Assuming Gaussian distribution for both capture cross section σ and activation energy E, the width of the activation energy ΔE is estimated to be 10∼16 meV and largest at x=0.45, while the relative broadening in the capture cross section is found to be Δσ/σ0∼1/3 from the shape of S(λ, T). The possible origin of the double peaks is tentatively assigned to DX-to-X conduction band and DX-to-L conduction band excitation for x=0.45 and 0.55.