Nitride‐based hetero‐field‐effect‐transistor‐type photosensors with extremely high photosensitivity

Abstract

AlGaN/GaN hetero‐field‐effect‐transistor‐type (HFET‐type) photosensors are fabricated with a p‐GaInN optical gate for the detection of visible light. These photosensors employ a two‐dimensional electron gas at the heterointerface between AlGaN and GaN as a highly conductive channel with a high electron mobility. By changing the InN molar fraction in the p‐GaInN optical gate, the wavelength range of the photosensitivity of the HFET‐type photosensors can be controlled. The photosensitivity of the AlGaN/GaN HFET‐type photosensors with a p‐GaInN optical gate greatly surpassed those of commercially available Si pin and Si avalanche photodiodes, and was comparable to those of photomultiplier tubes. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

High photosensitivity AlGaN/GaInN/GaN heterojunction field-effect transistor type visible photosensors

“…These dark current values correspond to a reduction of more than three orders of magnitude compared with the HFET-type photosensor reported so far with GaN as the underling layer. 25,26) Also within this experiment, we could not confirm the increase of the dark current density due to the insertion of the unintentionally doped GaN interlayer. Therefore, it has been confirmed that inserting the C-doped GaN underlying layer is useful for fabrication of photosensors with very low dark current.…”

“…[15][16][17][18][19][20] Thus far, we have reported high photosensitivity AlGaN/GaN heterostructure field effect transistor (HFET) type photosensors with p-type GaN optical gate, AlGaN/GaN HFET type photosensor with p-type GaInN optical gate, AlGaN/AlGaN HFET type photosensor with p-type GaN optical gate, and AlGaN/ AlGaN HFET type photosensor with Schottky electrode gate, respectively. [21][22][23][24][25][26][27][28][29] Since these HFET type photosensors have two-dimensional electron gas (2DEG) with high mobility, a large gain is obtained and as a result high photosensitivity is realized. By using p-type GaN or Schottky electrode, it is possible to expect a low dark current by forming a depletion layer, resulting in high rejection ratio as a result.…”

“…[27][28][29] We also reported the result of applying this device structure to photosensor with photosensitivity in visible light region. 25,26) In these reports, the photosensors with photosensitivity of 4 × 10 5 A W −1 at approximately 380 nm, rejection ratio of 17, and absorption wavelength edge of 450 nm were realized by using p-type GaInN gate. However, the photosensitivity is almost the value of GaN, it has serious problems that the low S/N ratio and the wavelength range required for visible light communication have not been reached.…”

Realization of high-performance hetero-field-effect-transistor-type ultraviolet photosensors using p-type GaN comprising three-dimensional island crystals

“…[1][2][3][4][5][6][7][8][9][10] Accordingly, it is necessary to develop UV photosensors with wavelength selectivity, low dark currents, and a low noise equivalent power. [11][12][13][14] As AlGaN ternary alloys have wide direct bandgaps ranging from 3.4 to 6.2 eV, they are suitable for photosensors that operate in the near-UV to deep-UV regions. 15,16) Previously, we reported the fabrication of AlGaN=AlGaN heterostructure-field-effect-transistor-type (HFET-type) photosensors with high sensitivity for UV light with wavelengths of 220-280 nm.…”

Control of the Detection Wavelength in AlGaN/GaN-Based Hetero-Field-Effect-Transistor Photosensors

“…The photosensitivity of these devices greatly surpassed those of commercially available Si pin and Si avalanche photodiodes, and was comparable to those of photomultiplier tubes. 21) Figure 1 shows schematic diagrams of the operating principle of this device. Such devices take advantage of the two-dimensional electron gas (2DEG) by means of the AlGaN/GaN heterostructure and depletion layer formed by the p-GaN optical gate.…”