The influence of defects on response speed of high gain two-beam photogating in a-Si:H PIN structures

Zollondz, J.-H.; Reynolds, S.; Main, C.; Smirnov, V. A.; Zrinscak, I.

doi:10.1016/s0022-3093(01)01204-2

Cited by 5 publications

(12 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, in case of dichromatic or multispectral illumination, the local low-field region might be offset so that the transport of electrons generated in the device front is facilitated. In result, a significantly larger amount of photogenerated electrons can drift towards the electrical contact so that collection efficiencies can exceed unity gain 27 , 29 , 33 . Such light-induced electrical field deformations enabled by photogating predominantly occur in defective materials, like a-Si:H, which exhibits a large amount of deep dangling bond states rather than localized tail states.…”

Section: Resultsmentioning

confidence: 99%

Amorphous silicon intrinsic photomixing detector for optical ranging

Bablich,

Müller,

Bornemann

et al. 2023

Commun Eng

View full text Add to dashboard Cite

Today’s optical range finders or 3D imagers suffer from significant drawbacks and do not allow to combine performance (sensitivity, precision) with simplicity, and scalability enabling very-large scale integration with minimum footprint. Here, we present the amorphous silicon Intrinsic Photomixing Detector (IPD) for direct and highly sensitive optical envelope mixing. The ability to generate a photocurrent that is proportional to the nonlinear mixing of two optical modulation envelope functions enables high performance Time-of-Flight optical ranging at low light levels down to $$\sim \!0.1\,{{{{{\rm{mW}}}}}}{{{{{\rm{cm}}}}}}^{-2}$$ ~ 0.1 mW cm − 2 at $$444\,{{{{{\rm{nm}}}}}}$$ 444 nm . The IPD exceeds MHz bandwidth, covers a broad distance detection range from $$10\,{{{{{\rm{cm}}}}}}$$ 10 cm to $$101\,{{{{{\rm{m}}}}}}$$ 101 m , and achieves a mean depth resolution below $$44\,{{{{{\rm{mm}}}}}}$$ 44 mm for distances up to $$25\,{{{{{\rm{m}}}}}}$$ 25 m . The IPD paves the way towards simple but high-performance photodetectors that allow for very-large scale integration on top of silicon or flexible electronics at low costs with pixel fill factors up to 100%.

show abstract

Section: Resultsmentioning

confidence: 99%

Amorphous silicon intrinsic photomixing detector for optical ranging

Bablich,

Müller,

Bornemann

et al. 2023

Commun Eng

View full text Add to dashboard Cite

show abstract

“…However, in contrast to their crystalline counterpart, the photocurrent in reverse biased a-Si:H p-i-n photodiodes can significantly exceed that expected from the generation of primary photo-induced charge carriers, if the device is photo-gated utilizing an additional gate beam [13,14].…”

Section: Introductionmentioning

confidence: 97%

“…A few years later, collection efficiency and photocurrent gain values up to almost 50 in the visible range have experimentally been demonstrated by Main et al [13] in comparatively thick photodetectors by applying high reverse bias voltages of -25 V. Unfortunately, absolute responsivities have not been reported impeding a quantitative performance comparison with the state-of-the-art. To achieve a sufficient device gating stability and such high optical gain values, extensive annealing and light-soaking prior to the measurements have been reported to be mandatory [13,14,16]. Initial degradation, e.g., by utilizing extensive AM1.0 illumination (AM: air mass coefficient), was required to generate an in-built low-field region in the front of the device that can be controlled and modulated by a weakly absorbed gate beam [13].…”

Section: Introductionmentioning

confidence: 99%

High Responsivity and Ultra-Low Detection Limits in Nonlinear a-Si:H p-i-n Photodiodes Enabled by Photogating

Bablich,

Müller,

Bornemann

et al. 2023

Photonic Sens

View full text Add to dashboard Cite

Photodetectors operating at the wavelength in the visible spectrum are key components in high-performance optoelectronic systems. In this work, massive nonlinearities in amorphous silicon p-i-n photodiodes enabled by the photogating are presented, resulting in responsivities up to 744 mA/W at blue wavelengths. The detectors exhibit significant responsivity gains at optical modulation frequencies exceeding MHz and a more than 60-fold enhanced spectral response compared to the non-gated state. The detection limits down to 10.4 nW/mm2 and mean signal-to-noise ratio enhancements of 8.5 dB are demonstrated by illuminating the sensor with an additional 6.6 µW/mm2 red wavelength. Electro-optical simulations verify photocarrier modulation due to defect-induced field screening to be the origin of such high responsivity gains. The experimental results validate the theory and enable the development of commercially viable and complementary metal oxide semiconductor (CMOS) compatible high responsivity photodetectors operating in the visible range for low-light level imaging and detection.

show abstract

“…To estimate the DOS in the lower part of band gap between the Fermi level and valence band edge, methods such as constant photocurrent method (CPM) [21], Fourier transform photocurrent spectroscopy (FTPS) [22,23], and dual beam photoconductivity (DBP) [24] were used in the past. On the other hand, the multiexponential trapping rate and modulated photocurrent (MPC) technique [25][26][27] allow determining parameters of localized states throughout the entire energy gap by employing frequency and temperature scans.…”

Section: Introductionmentioning

confidence: 99%

“…The aim of our research is the mammalian cells chemiluminescence detection, which is based on the phenomenon that under illumination of two-beam, low intensity probe beam and simultaneously a higher intensity bias beam, reverse-biased a-Si:H p-i-n photodiode photocurrent exceed expected primary photocurrent [26].…”

Section: Introductionmentioning

confidence: 99%

a-Si:H p-i-n Photodiode as a Biosensor

Gradišnik¹,

Gumbarević²

2018

Photodetectors [Working Title]

View full text Add to dashboard Cite

The p-in a-Si:H photodiode is a promising device as a transducer in biosensors. The native and light-induced localized state density and energy distribution in the energy gap of a-Si:H have a large effect on the photoconductivity of thin-film photodiodes. Depending on their nature, they play a crucial role in trapping and recombination processes and consequently influence the photodiode capacitance. The optical bias dependence of modulated photocurrent, OBMPC, method using the blue LED light is applied to clarify the nature and energy distribution of the energy gap density of states and their influence on the photodiode capacitance, from photodiodes transient response. It is observed that the deep defect states of the i-layer contribute to the capacitance at various bias voltages. Also, the capacitance achieves the upper limit around the built-in potential. Based on this method and obtained results, the a-Si:H p-in photodiode is used as a biosensor transducer in the detection of mammalian cell chemiluminescence.

show abstract

The influence of defects on response speed of high gain two-beam photogating in a-Si:H PIN structures

Cited by 5 publications

References 8 publications

Amorphous silicon intrinsic photomixing detector for optical ranging

Amorphous silicon intrinsic photomixing detector for optical ranging

High Responsivity and Ultra-Low Detection Limits in Nonlinear a-Si:H p-i-n Photodiodes Enabled by Photogating

a-Si:H p-i-n Photodiode as a Biosensor

Contact Info

Product

Resources

About