Comparative study of (0001) and (11-22) InGaN based light emitting diodes
Accepted version
Peer-reviewed
Repository URI
Repository DOI
Change log
Authors
Abstract
We have systematically investigated the doping of (11-22) with Si and Mg by metal-organic vapour phase epitaxy for light emitting diodes (LEDs). By Si doping of GaN we reached electron concentrations close to 1020cm-3, but the topography degrades above mid 1019cm-3. By Mg doping we reached hole concentrations close to 5 × 1017cm-3, using Mg partial pressures about 3' higher than those for (0001). Exceeding the maximum Mg partial pressure led to a quick degradation of the sample. Low resistivities as well as high hole concentrations required a growth temperature of 900 °C or higher. At optimised conditions the electrical properties as well as the photoluminescence of (11-22) p-GaN were similar to (0001) p-GaN. The best ohmic p-contacts were achieved by NiAg metallisation. A single quantum well LED emitting at 465nm was realised on (0001) and (11-22). Droop (sub-linear increase of the light output power) occurred at much higher current densities on (11-22). However, the light output of the (0001) LED was higher than that of (11-22) until deep in the droop regime. Our LEDs as well as those in the literature indicate a reduction in efficiency from (0001) over semi-polar to non-polar orientations. We propose that reduced fields open a loss channel for carriers.
Description
Keywords
Journal Title
Conference Name
Journal ISSN
1347-4065
Volume Title
Publisher
Publisher DOI
Sponsorship
Engineering and Physical Sciences Research Council (EP/H019324/1)
Engineering and Physical Sciences Research Council (EP/I012591/1)
Engineering and Physical Sciences Research Council (EP/M010589/1)
Engineering and Physical Sciences Research Council (TS/G001383/1)