Predicted band structures of III-V semiconductors in the wurtzite phase

Abstract

While non-nitride III-V semiconductors typically have a zincblende structure, they may also form wurtzite crystals under pressure or when grown as nanowhiskers. This makes electronic structure calculation difficult since the band structures of wurtzite III-V semiconductors are poorly characterized. We have calculated the electronic band structure for nine III-V semiconductors in the wurtzite phase using transferable empirical pseudopotentials including spin-orbit coupling. We find that all the materials have direct gaps. Our results differ significantly from earlier ab initio calculations, and where experimental results are available (InP, InAs and GaAs) our calculated band gaps are in good agreement. We tabulate energies, effective masses, and linear and cubic Dresselhaus zero-field spin-splitting coefficients for the zone-center states. The large zero-field spin-splitting coefficients we find may lead to new functionalities for designing devices that manipulate spin degrees of freedom.

Electronic band structure of wurtzite GaP nanowires via temperature dependent resonance Raman spectroscopy

“…Our finding is strongly supported by the fact that for all other III-V semiconductor NWs of WZ phase RR measured gap energy ( 9hh  7C ) is lower than the values estimated by De and Pryor in Ref. [19] using pseudopotential calculations. In a recent report the direct band gap (( 9hh  8C ) of GaP NWs is measured to be 2.09 eV using photoluminescence measurements [22], while the estimate of Ref.…”

“…In a report with full band structure pseudopotential model, the Raman gap is estimated to be 2.88 eV [19]. Our measured zero temperature value of ~2.47 eV falls in between these two estimates, and is not too far from the pseudopotential value.…”

“…According to Ref. [19], the value of E 2 is very small for GaP. Thus, taking E 2 ≈0 and the experimentally obtained values of E 1 and E 3 , we get cr  =0.29 eV and  so =0.…”

“…In a recent report the direct band gap (( 9hh  8C ) of GaP NWs is measured to be 2.09 eV using photoluminescence measurements [22], while the estimate of Ref. [19] is 2.25 eV. Table II summarizes the experimental measurements on WZ III-V NWs (including the one in the present work) compared to the estimates of De and Pryor (Ref.…”

“…As mentioned in the introduction, in case of GaP the E 1 (LO) phonon mode corresponds to coupling of electronic energy states with  9hh  7C ,  7V  7C and  9hh  8C transitions and the allowed intensity resonance of the A 1 (LO) mode corresponds to  7V  7C symmetry states of the electronic structure [10,21]. It is to be noted that for GaP band structure, the difference in energy between  9hh and 7lh is nearly zero [19]. Thus the resonance of both E 1 (LO) and A 1 (LO) modes at 2.67 eV in Fig.…”