been derived [,]. AlSb has been studied as being a potential material for high energy photon detection. It is an indirect bandgap material, and the calculated band structure is shown in (a), the minimum conduction band is at valley with the bandgap of 1.6 eV []. (b) shows the X band structure of AlAs, calculated by a method []. It is an indirect bandgap material with k×p the ordering of conduction band valley minima. The minimum bandgap is calculated as X-L-Γ 2.19 eV. For all the ternary III-V semiconductor compounds, the dependence of energy bandgap on alloy composition is assumed to fit to the equation of [] (2.6) where is the so called bowing parameter which accounts for the deviation from the Cbow linear interpolation between the bandgaps of the two binaries and The bowing parameter A B. is typically positive so that the alloy bandgap is smaller than the interpolation result and can be temperature dependent. Here we only focus on the parameter at room temperature. The recommended bowing parameter in AlAsSb for are 0.8, 0.28 and 0.28 EgΓ, EgX, EgL respectively []. The bandgap value of AlAs0.56Sb0.44 can be estimated from AlAs and AsSb [], as listed in . The minimum indirect valley bandgap is calculated as 1.84 eV, while there X is uncertainty in the bowing parameters that also introduces uncertainty in bandgap estimation of AlAs0.56Sb0.44. Responsivity measurements indicated that the cutoff wavelength of AlAs0.56Sb0.44 is around 750 nm which corresponding to the minimum bandgap of 1.65 eV. AlAs (eV) AlSb (eV) AlAs0.56Sb0.44 (eV) Cbow 3 2.3 0.8 2.49 EgΓ 2.16 1.6 0.28 1.84 EgX 2.35 2.21 0.28 2.22 EgL 2.1 Bandgaps of estimated AlAs, AlSb and AlAs0.56Sb0.44
been derived [,]. AlSb has been studied as being a potential material for high energy photon detection. It is an indirect bandgap material, and the calculated band structure is shown in (a), the minimum conduction band is at X valley with the bandgap of 1.6 eV []. (b) shows the band structure of AlAs, calculated by a k×p method []. It is an indirect bandgap material with the ordering of X-L-Γ conduction band valley minima. The minimum bandgap is calculated as 2.19 eV. For all the ternary III-V semiconductor compounds, the dependence of energy bandgap on alloy composition is assumed to fit to the equation of [] (2.6) where Cbow is the so called bowing parameter which accounts for the deviation from the linear interpolation between the bandgaps of the two binaries A and B. The bowing parameter is typically positive so that the alloy bandgap is smaller than the interpolation result and can be temperature dependent. Here we only focus on the parameter at room temperature. The recommended bowing parameter in AlAsSb for EgΓ, EgX, EgL are 0.8, 0.28 and 0.28 respectively []. The bandgap value of AlAs0.56Sb0.44 can be estimated from AlAs and AsSb [], as listed in . The minimum indirect X valley bandgap is calculated as 1.84 eV, while there is uncertainty in the bowing parameters that also introduces uncertainty in bandgap estimation of AlAs0.56Sb0.44. Responsivity measurements indicated that the cutoff wavelength of AlAs0.56Sb0.44 is around 750 nm which corresponding to the minimum bandgap of 1.65 eV. AlAs (eV) AlSb (eV) Cbow AlAs0.56Sb0.44 (eV) EgΓ 3 2.3 0.8 2.49 EgX 2.16 1.6 0.28 1.84 EgL 2.35 2.21 0.28 2.22 2.1 Bandgaps of estimated AlAs, AlSb and AlAs0.56Sb0.44
Thesis-Jingjing%2020130924%20final%20version.docx