Alloying induced degradation of the absorption edge of InAsxSb1−x

Abstract

InAsxSb 1−x alloys show a strong bowing in the energy gap, the energy gap of the alloy can be less than the gap of the two parent compounds. We demonstrate that a consequence of this alloying is a systematic degradation in the sharpness of the absorption edge. The alloy disorder induced band-tail (Urbach tail) characteristics are quantitatively studied for InAs 0.05 Sb 0.95 .

Investigation of carrier dynamics in Zn1−xMgxO by time-resolved photoluminescence

“…The influence of such fluctuations on the absorption and PL spectra of Zn 1 À x Mg x O has been reported in a number of experiments [4,13,15,17]. The alloy disorder results in the formation of localized states below the band edge, known as the Urbach tail [1,18]. The presence of these states affects both the emission spectrum and the dynamics of the excited carrier system [19,20].…”

Measurements of the Electric Field of Zero-Point Optical Phonons in GaAs Quantum Wells Support the Urbach Rule for Zero-Temperature Lifetime Broadening

“…(1) and (2). Six decades have accumulated overwhelming experimental evidence that this relationship, the Urbach-Martienssen rule [4][5][6][7][8][9][10][11][12][13][14][15], holds in materials ranging from glasses with extreme topological disorder [12,13] to compositionally pure single crystals [15], in a range of energy gaps between 150 meV [16] and 10 eV [9]. An interesting consequence of this empirical rule (to be put on more rigorous ground below) is that the Urbach slope is finite even at zero temperature.…”

“…(1). The Urbach focus is usually interpreted as the zero-temperature band gap of the disorder-free virtual crystal and is hence larger than the measured gap ( [12,16]; also see the Supplemental Material [22]). In Fig.…”

Carrier dynamics in (ZnMg)O alloy materials

“…The influence of such fluctuations on the absorption and PL spectra of Zn 1−x Mg x O has been reported in a number of experiments [4,13,17,18]. The alloy disorder results in the formation of localized states below the band edge [1,19]. The presence of these states affects both the emission spectrum and the dynamics of the excited carrier system [20,21].…”