Persistent photoconductivity in n-type GaN

Chen, H. M.; Chen, Y. F.; Lee, Meng-Chieh; Feng, M. S.

doi:10.1063/1.365859

Cited by 119 publications

(47 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When carriers are trapped, the surface potential changes and the escape of the trapped carriers are delayed. The defects inside the InP NWs in our devices may be similar to those reported by Chen et al for GaN thin film [313]. The high lattice mismatch (∼8.1%) between InP and Si causes dislocation defects at the InP/Si heterointerface [52].…”

Section: Surface Traps Passivation and Persistent Photoconductivitysupporting

confidence: 71%

“…Both bulk defects, such as vacancies, impurities, and surface states can collectively contribute to the long trapping of photogenerated excess carriers and manifest as a temporary boost in dark conductivity, which may exist for days or even years [316]. PPC studies have been reported for some structures, e.g., GaN thin films [311], [313], [314], [317]- [320], InGaN epitaxial films [315], GaNNWs [321], and InP NWs [322].…”

Section: Surface Traps Passivation and Persistent Photoconductivitymentioning

confidence: 99%

See 1 more Smart Citation

A Perspective on Nanowire Photodetectors: Current Status, Future Challenges, and Opportunities

Logeeswaran

Nayak

et al. 2011

IEEE J. Select. Topics Quantum Electron.

141

View full text Add to dashboard Cite

Abstract-One-dimensional semiconductor nanostructures (nanowires (NWs), nanotubes, nanopillars, nanorods, etc.) based photodetectors (PDs) have been gaining traction in the research community due to their ease of synthesis and unique optical, mechanical, electrical, and thermal properties. Specifically, the physics and technology of NW PDs offer numerous insights and opportunities for nanoscale optoelectronics, photovoltaics, plasmonics, and emerging negative index metamaterials devices. The successful integration of these NW PDs on CMOS-compatible substrates and various low-cost substrates via direct growth and transfer-printing techniques would further enhance and facilitate the adaptation of this technology module in the semiconductor foundries. In this paper, we review the unique advantages of NW-based PDs, current device integration schemes and practical strategies, recent device demonstrations in lateral and vertical process integration with methods to incorporate NWs in PDs via direct growth (nanoepitaxy) methods and transfer-printing methods, and discuss the numerous technical design challenges. In particular, we present an ultrafast surface-illuminated PD with 11.4-ps full-width at half-maximum (FWHM), edge-illuminated novel waveguide PDs, and some novel concepts of light trapping to provide a full-length discussion on the topics of: 1) low-resistance contact and interfaces for NW integration; 2) high-speed design and impedance matching; and 3) CMOS-compatible massmanufacturable device fabrication. Finally, we offer a brief outlook into the future opportunities of NW PDs for consumer and military application.

show abstract

Section: Surface Traps Passivation and Persistent Photoconductivitysupporting

confidence: 71%

Section: Surface Traps Passivation and Persistent Photoconductivitymentioning

confidence: 99%

A Perspective on Nanowire Photodetectors: Current Status, Future Challenges, and Opportunities

Logeeswaran

Nayak

et al. 2011

IEEE J. Select. Topics Quantum Electron.

141

View full text Add to dashboard Cite

show abstract

“…Photoconductive GaN detectors [2][3][4][5][6][7][8][9][10][11][12][13][14] have early attracted much interest because of their simplicity and high responsivity. Although Khan et al reported a fast and linear photoconductor with a visible rejection of more than four decades, 2 most of the groups working on these devices describe persistent photoconductivity (PPC) effects, [3][4][5][6][7][8][9][10][11][12][13] that is, the photoinduced increase in the conductivity persists for a long time after the light is removed.…”

Section: Introductionmentioning

confidence: 99%

Visible-blindness in photoconductive and photovoltaic AlGaN ultraviolet detectors

Monroy

Calle

Muñoz

et al. 1999

Journal of Elec Materi

View full text Add to dashboard Cite

The influence of the photodetection mechanism on the performance of AlGaN ultraviolet (UV) detectors is analyzed by studying the characteristics of photoconductors and photovoltaic Schottky diodes fabricated on the same samples. The photoconductive response below the bandgap is not a direct function of the absorption coefficient. Instead, it is amplified by the dominant photoconductive responsivity mechanism, which is attenuated as the chopping frequency increases. On the contrary, photovoltaic detectors are characterized by a sharp UV/visible contrast, mainly dependent on the absorption properties of the material. Thus, these detectors are more suitable for selective UV applications, such as ozone layer monitoring or flame detection.

show abstract

“…The yellow-band luminescence (YL) and persistent photoconductivity (PPC) have also been observed and extensively investigated in undoped and doped GaN. 8,9 A recent report claimed that PPC and YL in GaN are related to each other through defects associated with a broad deep level. 10 The origins of YL and PPC are still in debate.…”

mentioning

confidence: 99%

“…10 The origins of YL and PPC are still in debate. [8][9][10][11] In this work, a variety of undoped GaN with electron densities on the order of mid-10 16 cm -3 and with a Hall mobility varying from < 50 cm 2 /sV to > 500 cm 2 /sV at room temperature were investigated using temperature variable Hall effect measurements. The objective was to better understand what limits the Hall mobility of undoped GaN as well as its relationship with the PPC effect.…”

mentioning

confidence: 99%

The hall mobility and its relationship with persistent photoconductivity of undoped GaN

Wang

Chua

2000

Journal of Elec Materi

View full text Add to dashboard Cite

Special Issue PaperHall effect measurements have been widely used to characterize electrical properties of undoped and doped GaN. 1,2 The Hall mobility is indicative of electrical quality of undoped GaN in optimization of growth conditions. 3,4 Although a number of models have been proposed to explain anomalous behavior of the Hall mobility dependency on the electron density, 5-7 mechanism, which dominates the Hall mobility of undoped GaN, still remains unclear. The yellow-band luminescence (YL) and persistent photoconductivity (PPC) have also been observed and extensively investigated in undoped and doped GaN. 8,9 A recent report claimed that PPC and YL in GaN are related to each other through defects associated with a broad deep level. 10 The origins of YL and PPC are still in debate. [8][9][10][11] In this work, a variety of undoped GaN with electron densities on the order of mid-10 16 cm -3 and with a Hall mobility varying from < 50 cm 2 /sV to > 500 cm 2 /sV at room temperature were investigated using temperature variable Hall effect measurements. The objective was to better understand what limits the Hall mobility of undoped GaN as well as its relationship with the PPC effect.Undoped GaN samples were grown on (0001) orienTemperature-variable Hall effect measurements have been used to investigate the electrical properties of undoped GaN, which have the electron densities on the order of mid-10 16 cm -3 and a Hall mobility varying from < 50 cm 2 /sV to > 500 cm 2 /sV. We found that very strong ionized impurity scattering limits the Hall mobility of GaN. Illumination even at 77 K has very little effect on the electron density but can lead to a noticeable persistent increase of the Hall mobility. The induced persistent photoconductivity (PPC) effect is therefore related to the Hall mobility through intrinsic electrically active defects. The properties of those defects were further investigated by monitoring a transient change of resistivity after removal of illumination at different temperatures. It reveals that the recapturing process of excited electrons into illumination-neutralized defects is the mechanism responsible for the PPC effect of undoped GaN.Key words: Undoped GaN, Hall effect, persistent photoconductivity, Hall mobility tated sapphire by metal organic vapor phase epitaxy (MOVPE). Trimethylgallium (TMGa) and NH 3 were used as the precursors. The carrier gas was H 2 . Growth conditions for undoped 3 µm thick GaN were fixed, while growth parameters used for GaN buffer layers were widely changed to vary the doping concentration of the undoped GaN samples. Temperature-variable Hall effect measurements were carried out using a BIO-RAD Hall effect system over a temperature range of 90-500 K. The samples were in van der Pauw geometry using In dots as ohmic contacts. The samples were first measured at room temperature and then heated up to 500 K in the dark. Temperature-variable-Hall effect measurements were carried out from 500 K to 90 K in the dark. The Hall effect or simple resistivity measurements wer...

show abstract

Persistent photoconductivity in n-type GaN

Cited by 119 publications

References 21 publications

A Perspective on Nanowire Photodetectors: Current Status, Future Challenges, and Opportunities

A Perspective on Nanowire Photodetectors: Current Status, Future Challenges, and Opportunities

Visible-blindness in photoconductive and photovoltaic AlGaN ultraviolet detectors

The hall mobility and its relationship with persistent photoconductivity of undoped GaN

Contact Info

Product

Resources

About