Yohei Hashizume, Pablo O. Vaccaro and Akira Sugimura
Lateral Junction Light Emitting Devices Fabricated on GaAs(311)A-oriented Substrates
Abstract:Light emitting devices with an unconventional structure that includes a lateral p-n junction
were studied. This lateral p-n junction can be formed by taking the advantage of
the crystal orientation dependence of the amphoteric properties of silicon dopant in GaAs.
In this research, the lateral p-n junctions were fabricated with Si-doped GaAs epilayers
grown by molecular beam epitaxy (MBE) on GaAs(311)A-oriented substrates that were
patterned before growth to alternately expose slopes of different orientations. Two types of
lateral junction light emitting diodes (LEDs) and a lateral junction vertical-cavity surface-emitting
laser (VCSEL) were fabricated and measured. LEDs with an active layer composed
of GaAs/Al0.5Ga0.5As 30 periods multiple quantum well (MQW) were fabricated and the visible electoluminescence (EL) spectra was observed up to room temperature. Modulation doped LEDs with an active layer composed of an In0.2Ga0.8As/GaAs single quantum
well (SQW) with non-doped GaAs barriers were fabricated and peculiar EL spectra were
obtained. In the EL spectra a flat portion that is nearly independent of measurement
temperature shows the presence of a two-dimensional hole gas in the p-type region. An
optically-pumped VCSEL with an active layer composed of 5 In0.2Ga0.8As/GaAs quantum
wells (QWs) and non-doped GaAs barriers was fabricated. From PL spectra, high reflectivity
tuned DBRs were successfully fabricated with optimized oxidation conditions. On set of amplified spontaneous emission was obtained with very low excitation laser power of
60.6 mW.