Tuning the polarization-induced free hole density in nanowires graded from GaN to AlN
| Autor: | Sarwar, A. T. M. Golam, Carnevale, Santino D., Kent, Thomas F., Yang, Fan, McComb, David W., Myers, Roberto C. |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Appl. Phys. Lett. 106, 032102 (2015) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1063/1.4906449 |
| Popis: | We report a systematic study of p-type polarization induced doping in graded AlGaN nanowire light emitting diodes grown on silicon wafers by plasma-assisted molecular beam epitaxy. The composition gradient in the p-type base is varied in a set of samples from 0.7 %Al/nm to 4.95 %Al/nm corresponding to negative bound polarization charge densities of 2.2x10^18 cm^-3 to 1.6x10^19 cm^-3. Capacitance measurements and energy band modeling reveal that for gradients greater than or equal to 1.30 %Al/nm, the deep donor concentration is negligible and free hole concentrations roughly equal to the bound polarization charge density are achieved up to 1.6x10^19 cm^-3 at a gradient of 4.95 %Al/nm. Accurate grading lengths in the p- and n-side of the pn-junction are extracted from scanning transmission electron microscopy images and are used to support energy band calculation and capacitance modeling. These results demonstrate the robust nature of p-type polarization doping in nanowires and put an upper bound on the magnitude of deep donor compensation. Comment: 12 pages of text, 3 tables, and 3 figures |
| Databáze: | arXiv |
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