Improved solar-blind external quantum efficiency of back-illuminated AlxGa1−xN heterojunction pin photodiodes

Collins, Charles J.; Chowdhury, U.; Wong, M. M.; Ye, Bo; Beck, A.L.; Dupuis, R. D.; Campbell, Joe C.

doi:10.1049/el:20020526

Cited by 26 publications

(14 citation statements)

References 13 publications

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“…The typical detectivity of a cooled PMT is about cm Hz W around 300 nm [13]. A comparable detectivity performance ( cm Hz W at 275 nm) was reported recently with a solar-blind AlGaN-based back-illuminated p-i-n photodiode [14]. In this letter, we report the design, fabrication, and characterization of solar-blind AlGaN p-i-n photodiodes with record dark current and detectivity performance.…”

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confidence: 72%

Solar-Blind AlGaN-Based p-i-n Photodiodes With Low Dark Current and High Detectivity

Bıyıklı

Kimukin

Aytür

et al. 2004

IEEE Photon. Technol. Lett.

120

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Abstract-We report solar-blind Al Ga 1 N-based heterojunction p-i-n photodiodes with low dark current and high detectivity. After the p+ GaN cap layer was recess etched, measured dark current was below 3 fA for reverse bias values up to 6 V. The device responsivity increased with reverse bias and reached 0.11 A/W at 261 nm under 10-V reverse bias. The detectors exhibited a cutoff around 283 nm, and a visible rejection of four orders of magnitude at zero bias. Low dark current values led to a high differential resistance of 9.52 10 15 . The thermally limited detectivity of the devices was calculated as 4.9 10 14 cm Hz 1 2 W 1 .Index Terms-AlGaN, dark current, detectivity, heterostructure, high-performance, p-i-n photodiode. SOLAR-BLIND detectors with long-wavelength cutoff around 280 nm have important applications including missile plume sensing, flame detection, chemical-biological agent sensing, and covert space-to-space communications [1]. With the advent in material growth of high-quality Al Ga N ternary alloys, AlGaN-based solar-blind photodetectors emerged as a potential alternative for the photomultiplier tube (PMT) and silicon-based solar-blind detector technology. They have the advantage of intrinsic solar-blindness, and therefore, do not need complex and costly filters. In addition, AlGaN-based solar-blind detectors can operate under harsh conditions due to their wide bandgap and robust material properties [2]. Several research groups have demonstrated high-performance solar-blind photodetectors using Al Ga N material systemDetectivity is an important detector performance parameter which gives the signal-to-noise performance of the device. For low noise detection, detectivity should be as high as possible. The typical detectivity of a cooled PMT is about cm Hz W around 300 nm [13]. A comparable detectivity performance ( cm Hz W at 275 nm) was reported recently with a solar-blind AlGaN-based back-illuminated p-i-n photodiode [14]. In this letter, we report the design, fabrication, and characterization of solar-blind AlGaN p-i-n photodiodes with record dark current and detectivity performance. The measured dark current was below 3 fA at 6-V re- verse bias and a PMT-exceeding solar-blind detectivity of cm Hz W at 267 nm was achieved. The p-i-n photodiode wafer was grown by metal-organic chemical vapor deposition on sapphire substrate. The detector structure was designed for front (p-side) illumination. The active absorption region of the photodiode was formed with a 100-nm-thick unintentionally doped Al Ga N layer which was sandwiched between a 250-nm-thick n+ GaN layer and a 10-nm-thick p-type-doped Al Ga N layer. To improve the p-ohmic contact quality, a 30-nm-thick p-type GaN cap layer was grown on top of p-Al Ga N layer. A five-step microwave compatible semiconductor fabrication process was utilized to complete the device fabrication [15]. In the first two steps, ohmic contacts were formed. A 250-nm deep dry-etch for n+ ohmic contact was done via CCl F -based reactive ion etching (RIE). This was follow...

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supporting

confidence: 72%

Solar-Blind AlGaN-Based p-i-n Photodiodes With Low Dark Current and High Detectivity

Bıyıklı

Kimukin

Aytür

et al. 2004

IEEE Photon. Technol. Lett.

120

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“…The dark current of the 200 m diameter devices was measured to be on the order of 5 fA for bias voltages up to 10 V. The breakdown voltages were higher than 200 V. 13 have all been previously reported. AlGaNbased solar-blind photodetectors with breakdown voltages larger than 100 V, 136 mA/ W responsivity under 0 V bias at 282 nm, and 72% QE under 5 V reverse bias for backilluminated AlGaN p-i-n photodiode, 14 solar-blind focal plane arrays that possess 60% QE at 280 nm under 0 V bias, 15 dark current density of 8.2ϫ 10 −11 A / cm 2 under 5 V reverse bias, 16 and thermally limited detectivity of 4.9 ϫ 10 14 cm Hz 1/2 / W ͑Ref. 17͒ at 267 nm have also been reported.…”

Section: Solar-blind Algan-based P-i-n Photodetectors With High Breakmentioning

confidence: 99%

Solar-blind AlGaN-based p-i-n photodetectors with high breakdown voltage and detectivity

Tut

Yelboğa

Ulker

et al. 2008

Applied Physics Letters

111

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“…Peak responsivities and corresponding quantum efficiencies scatter in a wide range depending on the device design and material qualities. Recently, Collins et al [13] reported a peak responsivity for AlGaN solar-blind p-i-n photodiodes as high as 0.12 A/W at 275 nm without bias, giving an external quantum efficiency of 53%. This achievement was attributed to an improved material quality of Al 0:6 Ga 0:4 N. Design consideration and material quality are the key issues for achieving higher device performance.…”

Section: Introductionmentioning

confidence: 99%

GaN/AlGaN back-illuminated multiple-quantum-well Schottky barrier ultraviolet photodetectors

Teke

Doğan

Yun

et al. 2003

Solid-State Electronics

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We report on characterization and operation principle of a set of GaN/AlGaN multiple-quantum-well (MQW) photovoltaic detectors. The structures were grown by molecular beam epitaxy (MBE) on c-plane sapphire substrates and fabricated in the back-illuminated vertical Schottky geometry. Introduction of MQWs into the active region of devices is expected to enhance the quantum efficiency due to the high absorption coefficient. A nearly flat spectral responsivity between 325 and 350 nm with 0.054 A/W peak responsivity was achieved from the single-side polished backside (rough) illuminated GaN/AlGaN MQW devices. The cutoff wavelength of the MQW photodetector can be tuned by adjusting the well width, well composition and barrier height. A model has been developed to gain insight into the operation principles of MQWs photodiodes. The peak responsivity increased with decreasing barrier thickness due to enhanced tunneling of photogenerated carriers.

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Improved solar-blind external quantum efficiency of back-illuminated AlxGa1−xN heterojunction pin photodiodes

Cited by 26 publications

References 13 publications

Solar-Blind AlGaN-Based p-i-n Photodiodes With Low Dark Current and High Detectivity

Solar-Blind AlGaN-Based p-i-n Photodiodes With Low Dark Current and High Detectivity

Solar-blind AlGaN-based p-i-n photodetectors with high breakdown voltage and detectivity

GaN/AlGaN back-illuminated multiple-quantum-well Schottky barrier ultraviolet photodetectors

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