Study of Ill-V Nitride Semiconductor Resonant Cavity Enhanced Photodetector by Molecular Beam Epitaxy

The resonant cavity enhanced photodetector(RCE-PD)is expected to have wavelength selectivity，high quantum efficiency and high-speed characteristics.The photosensitivity characteristics of AlGaN based RCE-PD was theoretically investigate.Investigation of high-quality GaN growth on(0001)Al I D22 I D 2 O I D 23 ii substrates by molecular beam epitaxy using elemental Ga and re-plasma nitrogen as source was carried out.Extreme high-speed GaN growth of 2.6um/hr was also demonstrated by increase of radical nitrogen supply at the substrates.Novel shutter control technique in which nitrogen was alternately supplied during continuous Ga supply was applied for Mg doped GaN growth.As grown p-type GaN with low resistivity(p=2 x 10 I D 117 I D 1 cm I D 1-3 I D 1，ρ=3.8Ωcm)was obtained.The crystal polarity control technique was also demonstrated.The high-temperature grown AlN buffer layer brought about a Ga-polarity GaN growth and the high-temperature grown AlN intermediate layers(HT-AlN-ILs)with diffe…More rent thickness were found to play different roles in improvement of crystal quality。The 8 nm-thick HT-AlN-IL brought about improvement of electrical properties.On the other hand，the 2 nm-thick HT-AlN-IL improved surface morphology。The combination of these 8 nm-thick and 2 nm-thick HT-AlN-ILS improved both electrical property and surface morphology，concurrently.Nitrogen polarity-GaN could be grown on the Al ei D12锡D1O锡D13锡D1 substrates with enough initial nitridation by RF-plasma nitrogen.The GaN layers were grown with migration enhanced epitaxy(MEE)。The dislocation density of MEE-GaN remarkably reduced by insertion of the HT-AlN-ILs and it was clearly observed that most dislocations were bent during passing through the HT-AlN-IL.The dislocation density of MEE-GaN grown on HT-AlN-IL was evaluated to be about 2.1 x 10 I D 19 I D 1 cm I D 1-2 I D 1 by a selective photoelectrochemical wet etching，as a result，the highest RT mobility of 668 cm I D 12 I D 1/Vs was achieved.The AlGaN distributed Bragg reflectors for at blue and UV region were grown by molecular beam epitaxy using RF-plasma excited nitrogen.Relatively high reflectivity of 95%and 92%was achieved at the wavelength of 444 nm and 377 nm，respectively。Less：Less

The resonant cavity enhanced photodetector (RCE-PD) is expected to have wavelength selectivity, high quantum efficiency and high-speed characteristics. The photosensitivity characteristics of AlGaN based RCE-PD was theoretically investigate.Investigation of high-quality GaN growth on (0001) AlィイD22ィエD2OィイD23ィエD2 substrates by molecular beam epitaxy using elemental Ga and re-plasma nitrogen as source was carried out. Extreme high-speed GaN growth of 2.6um/hr was also demonstrated by increase of radical nitrogen supply at the substrates. Novel shutter control technique in which nitrogen was alternately supplied during continuous Ga supply was applied for Mg doped GaN growth. As grown p-type GaN with low resistivity (p=2x10ィイD117ィエD1cmィイD1-3ィエD1, ρ=3.8Ωcm) was obtained.The crystal polarity control technique was also demonstrated. The high-temperature grown AlN buffer layer brought about a Ga-polarity GaN growth and the high-temperature grown AlN intermediate layers (HT-AlN-ILs) with diffe … More rent thickness were found to play different roles in improvement of crystal quality. The 8nm-thick HT-AlN-IL brought about improvement of electrical properties. On the other hand, the 2nm-thick HT-AlN-IL improved surface morphology. The combination of these 8nm-thick and 2nm-thick HT-AlN-ILS improved both electrical property and surface morphology, concurrently.Nitrogen polarity-GaN could be grown on the AlィイD12ィエD1OィイD13ィエD1 substrates with enough initial nitridation by RF-plasma nitrogen. The GaN layers were grown with migration enhanced epitaxy (MEE). The dislocation density of MEE-GaN remarkably reduced by insertion of the HT-AlN-ILs and it was clearly observed that most dislocations were bent during passing through the HT-AlN-IL. The dislocation density of MEE-GaN grown on HT-AlN-IL was evaluated to be about 2.1x10ィイD19ィエD1cmィイD1-2ィエD1 by a selective photoelectrochemical wet etching, as a result, the highest RT mobility of 668cmィイD12ィエD1/Vs was achieved.The AlGaN distributed Bragg reflectors for at blue and UV region were grown by molecular beam epitaxy using RF-plasma excited nitrogen. Relatively high reflectivity of 95% and 92% was achieved at the wavelength of 444nm and 377nm, respectively. Less