The influence of magnesium on p-type doping and optoelectronic properties of Zn1−xMgxSe-based heterostructures

Structural and electronic properties of wide band gap Zn1−xMgxSe alloys

“…For example, for a RT lattice parameter of 5.74 Å, the band gap values reported in the literature range from ϳ2.91 to ϳ2.98 eV, corresponding to an uncertainty of 2%-3%. Our data are in remarkable agreement with those by Okuyama et al 7 and by Puls et al, 8 while appreciable differences exist as compared to the data reported by Vögele et al 9 and Wörz et al 10…”

“…6, with our data occupying the middle range of a wide distribution of reported values. For example, a lattice parameter of 5.79 Å corresponds to reported Mg concentrations varying from ϳ40% ͑Puls et al͒ 8 to ϳ55% ͑Vögele et al͒, 9 with a resulting uncertainty of about 30% in alloy composition for a given lattice parameter. Discrepancies grow even larger when the results of Fig.…”

“…However, substantial discrepancies still exist in the literature between the reported properties of this prototype alloy system. [6][7][8][9][10] Jobst et al have published the only investigation of the band gap and lattice parameter of Zn 1Ϫx Mg x Se alloys throughout the 0%-95% Mg concentration range. 6 The lattice parameter was determined from x-ray diffraction ͑XRD͒ studies, the alloy composition from electron probe microanalysis ͑EPMA͒, and the band gap E g from optical transmission and reflection measurements.…”

“…This would suggest a RT band gap value of 3.91 eV. 15 A different method of evaluating the Mg concentration was applied by Vögele et al, 9 who studied Zn 1Ϫx Mg x Se alloys with x up to 0.4 using secondary ion mass spectrometry ͑SIMS͒ and XRD, and evaluated the LT band gap from reflectivity measurements. No evidence of bowing in the x dea͒ pendence of the lattice parameter was reported, with an extrapolated value of the MgSe lattice parameter of 5.894 Å, i.e., very close to the value predicted by Okuyama et al 7 Conversely, the x dependence of the LT band gap was found to deviate from linearity, with a bowing parameter b E ϭϩ0.350 eV.…”