Browsing by Subject "Avalanche photodiodes"
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Item Avalanche photodiodes as single photon detectors(2005) Karve, Gauri Vibhakar; Campbell, JoeItem Avalanche photodiodes with low noise, high speed and PIN photodetectors with high output power(2006) Duan, Ning; Campbell, Joe C.Item High performance ultraviolet 4H-SiC avalanche photodiodes(2005) Guo, Xiangyi; Campbell, Joe C.Item Long-wavelength, high-speed avalanche photodiodes and APD arrays(2004) Zheng, Xiaoguang; Campbell, JoeItem Low noise avalanche photodiodes with an impact-ionization-engineered multiplication region(2002-08) Wang, Shuling, 1972-; Campbell, JoeAn avalanche photodiode (APD) is frequently the photodetector of choice in high-bit-rate, long-haul fiber optic communication systems due to its higher sensitivity, relative to a PIN photodiode, afforded by its internal gain. However, this can only be accomplished given that the multiplication noise is low. Impactionization-engineering (I2 E) is a novel approach that incorporates materials with different impact ionization threshold energies (Eth) into the multiplication region of APDs for low noise, high gain, and low dark current. A series of multiplication region structures with record-low multiplication noise were developed on both GaAs and InP substrates; an excess noise level comparable to silicon APDs was achieved on I2 E structures grown on GaAs. Unlike “superlattice” or “staircase” structures, the band gap continuities are not involved in the working mechanism of I2 E APDs. Monte Carlo simulation has revealed the spatial modulation effect of the impact ionization events in these heterostructure devices, which makes the ionization process more deterministic than in homojunctions, thus yielding lower noise. These low-noise I2 E multiplication region structures are promising in improving APD performance once they are implemented into SACM structures, with working wavelengths including 800-900nm, 1.3µm, and 1.55µm.Item Molecular-beam epitaxial growth of low-dark-current avalanche photodiodes(2007-12) Hurst, Jeffrey Byron, 1977-; Holmes, Archie L.The quaternary material system In[subscript x]Ga[subscript 1-x]As[subscript y]P[subscript 1-y] is an important material system for optoelectronic devices, specifically covering optimum fiber optic wavelengths. Among the limitations of using this material system concerning photodetector performance is generation of carriers due to material defects and impurities. This dissertation reports on the growth optimization of InGaAs using molecular-beam epitaxy for low-dark-current avalanche photodiodes through the study of the effects of the growth conditions on dark current. An optimum growth temperature of 545°C and arsenic beam equivalent pressure of 2x10⁻⁵ Torr was found for producing the lowest dark current density. Avalanche photodiodes were implemented with a dark current density 80 mA/cm² at 90% of the breakdown voltage.Item Monte Carlo simulation of gain, noise, and speed of low-noise and high-speed avalanche photodiodes(2003-08) Ma, Feng, 1973-; Campbell, JoeA Monte Carlo simulation model is developed. The low-noise behavior of AlGaAs/GaAs avalanche photodiodes (APDs) is successfully simulated and is explained as spatial localization of impact ionization events. The noise is sensitive to initial carrier energy and we point out that energetic and hot electrons should be distinguished. This model also successfully explains the measured exponential gain curve and “noiseless” behavior of HgCdTe APDs. I demonstrate that this model can aid the design of high-speed InGaAs/InAlAs APDs. Model parameters are constrained with low-temperature measurements of APD gain and noise in this work. I have also suggested a new shot noise suppression mechanism associated with multiplication gain.Item Wide band gap avalanche photodiodes for ultraviolet single photon detection(2006-05) Beck, Ariane Laura, 1979-; Campbell, Joe