Showing papers by "Adam William Saxler published in 1996"
TL;DR: In this article, the spectral responsivity of the GaN detector at 360 nm is about 1 A/W biased at 8 V at room temperature, and the carrier lifetime derived from the voltage-dependent responsivity is 0.13−0.36 ms.
Abstract: AlxGa1−xN (0≤x≤0.50) ultraviolet photoconductors with a minimum cutoff wavelength shorter than 260 nm have been fabricated and characterized. The AlGaN active layers were grown on (00⋅1) sapphire substrates by metalorganic chemical vapor deposition (MOCVD). The spectral responsivity of the GaN detector at 360 nm is about 1 A/W biased at 8 V at room temperature. The carrier lifetime derived from the voltage‐dependent responsivity is 0.13–0.36 ms.
176 citations
TL;DR: In this paper, the metalorganic chemical vapor deposition growth and characterization of monocrystalline GaN thin films on β-LiGaO2 substrates was reported, and structural, electrical, and optical properties of the films were assessed through scanning electron microscopy, x-ray diffraction, Hall measurements, optical transmission, and photoluminescence.
Abstract: We report the metalorganic chemical vapor deposition growth and characterization of monocrystalline GaN thin films on β‐LiGaO2 substrates The influence of the growth temperature on the crystal quality was studied The structural, electrical, and optical properties of the films were assessed through scanning electron microscopy, x‐ray diffraction, Hall measurements, optical transmission, photoluminescence
62 citations
TL;DR: In this paper, an optically pumped surface-emitting stimulated emission at room temperature was observed from GaN:Ge grown by metalorganic chemical vapor deposition, where the sample was pumped perpendicularly on the top surface while the stimulated emission was collected from the back colinearly with the pump beam.
Abstract: Optically pumped surface‐emitting stimulated emission at room temperature was observed from GaN:Ge grown by metalorganic chemical vapor deposition. The sample was optically pumped perpendicularly on the top surface while the stimulated emission was collected from the back colinearly with the pump beam. The cavity was formed by the GaN/air and GaN/sapphire interfaces without any other structure. The stimulated emission was gain guided by the pump beam. The threshold optical pump density for stimulated emission was approximately 2.8 MW/cm2 and the linewidth was 2.5 nm. The emission from GaN:Ge showed a redshift as the pump density increased. The comparison between theoretical calculations and experimental results suggested that many‐body interactions can account well for the redshift.
18 citations
TL;DR: In this paper, the metalorganic chemical vapor deposition growth, n-type and p-type doping and characterization of AlxGa1-xN alloys on sapphire substrates were presented.
Abstract: We present the metalorganic chemical vapor deposition growth, n-type and p-type doping and characterization of AlxGa1-xN alloys on sapphire substrates. We report the fabrication of Bragg reflectors and the demonstration of two dimensional electron gas structures using AlxGa1-xN high quality films. We report the structural characterization of the AlxGa1-xN / GaN multilayer structures and superlattices through X-ray diffraction and transmission electron microscopy. A density of screw and mixed threading dislocations as low as 107 cm-2 was estimated in AlxGa1-xN / GaN structures. The realization of AlxGa1-xN based UV photodetectors with tailored cut-off wavelengths from 365 to 200 nm are presented.
16 citations
TL;DR: In this article, the interface trap level density was calculated to be in the range of 1011 cm −2eV −1 from capacitance-voltage and conductance voltage measurements at high and low frequencies.
Abstract: AlN has been grown on Si(111) substrates by metal organic chemical vapour deposition. The formation of an inversion layer on n-type Si(111) has been clearly observed by capacitance-voltage measurements at high and low frequencies. The interface trap level density was calculated to be in the range of 1011 cm–2eV–1 from capacitance-voltage and conductance-voltage measurements.
12 citations
TL;DR: In this paper, the authors used reciprocal space maps of both symmetric and asymmetric reciprocal lattice points to determine that the cause of the broadening of GaN rocking curves is a limited in-plane coherence length.
Abstract: X-ray rocking curves are frequently used to assess the structural quality of GaN thin films. In order to understand the information given by the line shape, we need to know the primary mechanism by which the curves are broadened. The GaN films used in this study were grown by low pressure metalorganic chemical vapor deposition (MOCVD) on (00•1) sapphire substrates. GaN films with both broad and very narrow (open detector linewidth of 40 arcseconds for the (00•2) GaN reflection) rocking curves are examined in this work. Reciprocal space maps of both symmetric and asymmetric reciprocal lattice points are used to determine that the cause of the broadening of GaN rocking curves is a limited in-plane coherence length.
8 citations
12 Apr 1996
TL;DR: In SPIE Proceeding 2397, it was suggested that a particularly promising future technology is one based on the ability of investigators to produce high-quality films made of wide bandgap III-IV semiconductors as discussed by the authors.
Abstract: In SPIE Proceeding 2397 we demonstrated that there is a large payoff still to be gained by further improvements in the performance of solar blind UV detectors for astronomical purposes. We suggested that a particularly promising future technology is one based on the ability of investigators to produce high-quality films made of wide bandgap III-IV semiconductors. Here we report on significant progress we have made over the past year to fabricate and test single-pixel devices. The next step will be to measure and improve detective efficiency, measure the solar blindness over a larger dynamic range, and begin developing multiple-pixel designs.
4 citations
12 Apr 1996
TL;DR: In this article, metalorganic chemical vapor deposition was used to deposit AlxGa1-xN active layers with varying aluminum compositions on a basal plane sapphire substrate, and they were fabricated and characterized with cut-off wavelengths as short as 260 nm.
Abstract: Metalorganic chemical vapor deposition was used to deposit AlxGa1-xN active layers with varying aluminum compositions on basal plane sapphire substrate. AlxGa1-xN (x < 0.5) ultraviolet photodetectors have been fabricated and characterized with cut-off wavelengths as short as 260 nm. Carrier lifetimes on the order of 10 milliseconds were estimated from frequency dependent measurements of the responsivity.
1 citations