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in creator/contributor: "Hammons, B.E."

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Manufacturability of vertical-cavity surface emitting lasers grown by organometallic vapor phase epitaxy

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Date: January 1996

Creator: Hou, H. Q.; Chui, H. C.; Hammons, B. E.; Breiland, W. G. & Choquette, K. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

In situ growth rate measurements by normal-incidence reflectance during MOVPE growth

We present an in situ technique for monitoring metal-organic vapor phase epitaxy growth by normal-incidence reflectance. This technique is used to calibrate the growth rate periodically and to monitor the growth process routinely. It is not only a precise tool to measure the growth rate, but also very useful in identifying unusal problems during a growth run, such as depletion of source material, deterioration of surface morphology, and problems associated with an improper growht procedure. We … more

Date: May 1, 1996

Creator: Hou, H.Q.; Breiland, W.G.; Hammons, B.E. & Chui, H.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Surface-emitting semiconductor laser for intracavity spectroscopy and microscopy

The authors demonstrate lasing action in a novel microcavity laser which can be utilized for intracavity spectroscopy as well as high contrast imaging of small ({approximately} 10{mu}m) structures. The system can be easily visualized as a Fabry-Perot cavity containing a gain media and an object for study. Since the primary constraint on the object is transparency at the lasing wavelength, investigation of lasing in objects such as microspheres, liquid droplets, and biological cells is possible.… more

Date: March 1, 1995

Creator: Meissner, K. E.; Gourley, P. L.; Brennan, T. M.; Hammons, B. E. & McDonald, A. E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Highly uniform and reproducible vertical-cavity surface emitting lasers grown by metalorganic chemical vapor deposition

We show that the uniformity of the lasing wavelength of vertical-cavity surface emitting lasers (VCSELs) can be as good as {plus_minus}0.3% across a entire 3 in. wafer in MOCVD growth with a similar run-to-run reproducibility.

Date: January 1, 1996

Creator: Hou, H. Q.; Chui, H. C.; Choquette, K. D.; Hammons, B. E.; Breiland, W. G. & Geib, K. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mirror reflectivity and doping considerations for high performance oxide-confined vertical cavity lasers

We report the effects of mirror doping and reflectivity in 850 and 780 nm oxide-confined vertical cavity surface emitting lasers. Decreased doping throughout the n-type mirror produces significantly higher quantum efficiency, while the optimum reflectivity is dependent upon the gain material.

Date: January 1, 1996

Creator: Geib, K.M.; Choquette, K. D.; Chui, H. .; Hou, H. Q. & Hammons, B. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

InGaAsN Solar Cells with 1.0eV Bandgap, Lattice Matched to GaAs

The design, growth by metal-organic chemical vapor deposition, and processing of an In{sub 0.07}Ga{sub 0.93}As{sub 0.98}N{sub 0.02} solar Al, with 1.0 ev bandgap, lattice matched to GaAs is described. The hole diffusion length in annealed, n-type InGaAsN is 0.6-0.8 pm, and solar cell internal quantum efficiencies > 70% arc obwined. Optical studies indicate that defects or impurities, from InGAsN doping and nitrogen incorporation, limit solar cell performance.

Date: November 24, 1998

Creator: Allerman, A. A.; Banas, J. J.; Gee, J. M.; Hammons, B. E.; Jones, E. D. & Kurtz, S. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Threshold properties of a microcavity laser with submicroampere threshold current

We report the threshold characteristics of small oxide-confined vertical-cavity surface emitting lasers. Abrupt threshold transitions 105 times the spontaneous emission background are obtained at injection currents as low as 470 nanoampere.

Date: February 1, 1996

Creator: Choquette, K. D.; Hou, H. Q.; Lear, K. L.; Chow, W. W.; Mar, A.; Geib, K. M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Composite fermions in 2 {times} 10{sup 6} cm{sup 2}/Vs mobility AlGaAs/GaAs heterostructures grown by MOCVD

The authors report on the recent growth by MOCVD of 2.0 {times} 106 cm2/Vs mobility heterostructures. These mobilities, the highest reported to date, are attributed to the use of tertiarybutylarsine as the arsenic precursor. Measurements in tilted magnetic fields of the fractional quantum Hall effect (FQHE) states near filling factor 3/2 are consistent with a spin-split composite fermion (CF) model proposed earlier. The extracted values of the product of the CF g-factor and CF effective mass ag… more

Date: August 1, 1996

Creator: Simmons, J. A.; Chui, H. C.; Harff, N. E.; Hammons, B. E.; Du, R. R. & Zudov, M. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

In situ pre-growth calibration using reflectance as a control strategy for MOCVD fabrication of device structures

In situ normal incidence reflectance, combined with a virtual interface model, is being used routinely on a commercial MOCVD reactor to measure growth rates of compound semiconductor films. The technique serves as a pre-growth calibration tool analogous to the use of RHEED in MBE as well as a real-time monitor throughout the run. An application of the method to the growth of a vertical cavity surface emitting laser (VCSEL) device structure is presented. All necessary calibration information can… more

Date: August 1, 1996

Creator: Breiland, W.G.; Hou, H.Q.; Chui, H.C. & Hammons, B.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Growth of vertical-cavity surface emitting lasers by metalorganic vapor phase epitaxy

We present growth and characterization of visible and near-infrared vertical-cavity surface emitting lasers (VCSELs) grown by metalorganic vapor phase epitaxy. Discussions on the growth issue of VCSEL materials include growth rate and composition control using an {ital in}{ital situ} normal-incidence reflectometer, comprehensive p- and n-type doping study in AlGaAs by CCl{sub 4} and Si{sub 2}H{sub 6} over the entire composition range, and optimization of ultra-high material uniformity. We also … more

Date: October 1, 1996

Creator: Hou, H. Q.; Hammons, B. E.; Crawford, M. H.; Lear, K. L. & Choquette, K. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Wet oxidation of AlGaAs vs. AlAs: A little gallium is good

Buried oxides formed from the wet oxidation of AlGaAs alloys, rather than AlAs, are found to be superior in terms of oxidation isotropy, mechanical stability, and strain. It is not surprising that vertical-cavity surface-emitting lasers (VCSELs) using AlGaAs oxide layers as current apertures have shown promising reliability as compared to VCSELs using AlAs layers. Comparisons of lifetime data for VCSELs with differing oxide layers is presented. The beneficial properties of oxides converted from… more

Date: December 1996

Creator: Choquette, K. D.; Geib, K. M.; Hou, H. Q.; Lear, K. L.; Chui, H. C.; Hammons, B. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Origin of the Time-Dependence of Wet Oxidation of AlGaAs

The time-dependence of the wet oxidation of high-Al-content AlGaAs can be either linear, indicating reaction-rate limitation, or parabolic, indicating diffusion-limited rates. The transition from linear to parabolic time dependence can be explained by the increased rate of the formation of intermediate As{sub 2}O{sub 3} vs. its reduction to elemental As. A steadily increasing thickness of the As{sub 2}O{sub 3}-containing region at the oxidation front will shift the process from the linear to th… more

Date: February 15, 1999

Creator: Allerman, A. A.; Ashby, C. I. H.; Bridges, M. M.; Hammons, B. E. & Hou, H. Q.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Cavity structures for low loss oxide-confined VCSELs

The authors examine the threshold characteristics of selectively oxidized VCSELs as a function of the number, thickness, and placement of the buried oxide apertures. The threshold current density for small area VCSELs is shown to increase with the number of oxide apertures in the cavity due to increased optical loss, while the threshold current density for broad area VCSELs decreases with increasing number of apertures due to more uniform current injection. Reductions of the threshold gain and … more

Date: May 1997

Creator: Choquette, K. D.; Hadley, G. R.; Chow, W. W.; Hou, H. Q.; Geib, K. M.; Hammons, B. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Hydrogen implanted 1.3 {micro}m vertical cavity surface-emitting lasers with dielectric and wafer-boned GaAs/AlAs mirrors

A 1.3 {micro}m wavelength vertical-cavity surface-emitting laser (VCSEL) containing proton implanted isolation regions and a dielectric top mirror and a wafer-bonded GaAs/AlAs bottom mirror was fabricated. A room temperature pulsed threshold current density of 1.13 kA/cm{sup 2} and a threshold current of 2 mA have been demonstrated.

Date: May 1, 1997

Creator: Qian, Y.; Zhu, Z.H.; Lo, Y.H.; Huffaker, D.L.; Deppe, D.G.; Hou, H.Q. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Wet oxidation of Al{sub x}GA{sub 1-x}As: arsenic barriers on the road to mis

Three characteristic regimes were identified during wet thermal oxidation of AlxGa(1-x)As (x=1 to 0.90) on GaAs: oxidation of Al and Ga in the alloy to form to an amorphous oxide layer, formation and elimination of elemental As and of amorphous As2O3, and crystallization of the oxide film. Residual As can produce up to a 100fold increase in leakage current and a 30% increase in bulk dielectric constant. Very low As levels produce partial Fermi-level pinning at the oxidized AlxGa(1-x)As/GaAs int… more

Date: February 1, 1997

Creator: Ashby, C. I. H.; Sullivan, J. P.; Newcomer, P. P.; Missert, N. A.; Hou, H. Q.; Hammons, B. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Composite fermions in 2 x 10{sup 6} cm{sup 2}/Vs mobility A1GaAs/GaAs heterostructures grown by MOCVD

Recent growth by MOCVD (metalorganic chemical vapor deposition) of 2.0x10{sup 6} cm{sup 2}/Vs mobility heterostructures are reported. These mobilities, the highest reported to date, are attributed to use of tertiarybutylarsine as the arsenic precursor. Measurements in tilted magnetic fields of the fractional quantum Hall effect states near filling factor 3/2 are consistent with a spin-split composite fermion (CF) model proposed earlier. Extracted values of the product of the CF g-factor and CF … more

Date: December 31, 1996

Creator: Simmons, J.A., Chui, H.C., Harff, N.E., Hammons, B.E. & Du, R.R., Zudov, M.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

In-situ spectral reflectance for improving molecular beam epitaxy device growth

This report summarizes the development of in situ spectral reflectance as a tool for improving the quality, reproducibility, and yield of device structures grown from compound semiconductors. Although initially targeted at MBE (Molecular Beam Epitaxy) machines, equipment difficulties forced the authors to test most of their ideas on a MOCVD (Metal Organic Chemical Vapor Deposition) reactor. A pre-growth control strategy using in situ reflectance has led to an unprecedented demonstration of proc… more

Date: May 1, 1997

Creator: Breiland, W.G.; Hammons, B.E.; Hou, H.Q.; Killeen, K.P.; Klem, J.F.; Reno, J.L. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Stimulated emission from semiconductor microcavities

Laser-like emissions from semiconductor microcavities at low temperature have attracted considerable attention recently because of the possibility of realizing a non-equilibrium condensate by using cavity-polaritons. In this paper the authors present experimental studies of optical properties of a microcavity near the lasing threshold. They show that the minimum lasing threshold is achieved when the cavity is tuned significantly below the exciton line center. By comparing emission spectra with … more

Date: April 1, 1997

Creator: Fan, X.; Wang, H.; Hou, H.Q. & Hammons, B.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Highly uniform and reproducible visible to near-infrared vertical-cavity surface-emitting lasers grown by MOVPE

The authors present the growth and characterization of vertical-cavity surface emitting lasers (VCSELs) from visible to near-infrared wavelength grown by metalorganic vapor phase epitaxy. Discussions on the growth issue of VCSEL materials include the control on growth rate and composition using an in situ normal-incidence reflectometer, optimization of ultra-high material uniformity, and comprehensive p- and n-type doping study in AlGaAs by CCl{sub 4} and Si{sub 2}H{sub 6} over the entire Al co… more

Date: May 1, 1997

Creator: Hou, H. Q.; Choquette, K. D.; Hammons, B. E.; Breiland, W. G.; Crawford, M. H. & Lear, K. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Anomalous normal mode oscillations in semiconductor microcavities

Semiconductor microcavities as a composite exciton-cavity system can be characterized by two normal modes. Under an impulsive excitation by a short laser pulse, optical polarizations associated with the two normal modes have a {pi} phase difference. The total induced optical polarization is then expected to exhibit a sin{sup 2}({Omega}t)-like oscillation where 2{Omega} is the normal mode splitting, reflecting a coherent energy exchange between the exciton and cavity. In this paper the authors p… more

Date: April 1, 1997

Creator: Wang, H.; Hou, H.Q. & Hammons, B.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Fabrication issues of oxide-confined VCSELs

To insert high-performance oxide-confined vertical-cavity surface- emitting lasers (VCSELs) into the manufacturing arena, we have examined the critical parameters that must be controlled to establish a repeatable and uniform wet thermal oxidation process for AlGaAs. These parameters include the AlAs mole fraction, sample temperature, carrier gas flow, and bubbler water temperature. Knowledge of these parameters has enable the compilation of oxidation rate data for AlGaAs which exhibits an Arrhe… more

Date: April 1, 1997

Creator: Geib, K. M.; Choquette, K. D.; Hou, H. Q. & Hammons, B. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

In situ reflectance and virtual interface analysis for compound semiconductor process control

The authors review the use of in-situ normal incidence reflectance, combined with a virtual interface model, to monitor and control the growth of complex compound semiconductor devices. The technique is being used routinely on both commercial and research metal-organic chemical vapor deposition (MOCVD) reactors and in molecular beam epitaxy (MBE) to measure growth rates and high temperature optical constants of compound semiconductor alloys. The virtual interface approach allows one to extract … more

Date: May 1, 1998

Creator: Breiland, W.G.; Hou, H.Q.; Hammons, B.E. & Klem, J.F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Selectively oxidized vertical-cavity laser performance and technology

The authors discuss revolutionary performance advances in selectively oxidized vertical-cavity surface emitting lasers (VCSELs), which have enabled low operating power laser diodes appropriate for aerospace applications. Incorporating buried oxide layers converted from AIGaAs layers within the laser cavity produces enhanced optical and electrical confinement enabling superior laser performance, such as high efficiency and modulation bandwidth. VCSELs also shown to be viable over varied environm… more

Date: February 1, 1998

Creator: Choquette, K. D.; Hou, H. Q.; Geib, K. M. & Hammons, B. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

In-situ optical photoreflectance during MOCVD

This report summarizes the development of in situ optical photoreflectance as a tool for measuring impurity concentrations in compound semiconductors. The authors have successfully explored the use of photoreflectance as an in situ tool for measuring n-type doping levels in metal-organic chemical vapor deposition (MOCVD) grown GaAs materials. The technique measures phase and frequency shifts in Franz-Keldysh oscillations measured on uniformly doped thin films. Doping concentrations from 5 {time… more

Date: January 1, 1998

Creator: Breiland, W.G.; Hammons, B.E.; Hou, H.Q. & Mei, X.B.

Item Type: Report

Partner: UNT Libraries Government Documents Department