Optoelectronic and electronic devices based on quantum dots having proximity-placed acceptor impurities, and methods therefor

Solid-state optoelectronic and electronic devices that use semiconductor quantum dots for manipulation of photonic or electronic properties include a semiconductor active region forming a quantum dot heterostructure having a plurality of quantum dot layers each having discrete quantum hole states and a p-type impurity layer formed proximate to at least one of the quantum dot layers to provide excess equilibrium hole charge to occupy at least some of the discrete quantum hole states to improve To and other performance characteristics of quantum dot devices.Board of Regents, University of Texas Syste

Design and characterization of quantum dot photonic crystal lasers

Quantum dot photonic crystal lasers are demonstrated at room temperature by optical pulse pumping. Coupled cavities were designed based on square lattice PC slabs. Optimized two-dimensional photonic crystal cavities were defined in 200nm slabs with five-stacked InAS QDs layers. The two- and four-coupled cavities showed as incident pump power threshold as 120μW and 370μW, respectively, both from QD ground state emission range. Both clear threshold in pump power-output resonance power and resonance line width narrowing were observed from our membrane samples. The measured wavelengths matched very well with wavelengths predicted by 3D-Finite Difference Time Domain modelling

Robust Parallel Laser Driving of Quantum Dots for Multiplexing of Quantum Light Sources

Deterministic sources of quantum light (i.e. single photons or pairs of entangled photons) are required for a whole host of applications in quantum technology, including quantum imaging, quantum cryptography and the long-distance transfer of quantum information in future quantum networks. Semiconductor quantum dots are ideal candidates for solid-state quantum emitters as these artificial atoms have large dipole moments and a quantum confined energy level structure, enabling the realization of single photon sources with high repetition rates and high single photon purity. Quantum dots may also be triggered using a laser pulse for on-demand operation. The naturally-occurring size variations in ensembles of quantum dots offers the potential to increase the bandwidth of quantum communication systems through wavelength-division multiplexing, but conventional laser triggering schemes based on Rabi rotations are ineffective when applied to inequivalent emitters. Here we report the demonstration of the simultaneous triggering of >10 quantum dots using adiabatic rapid passage. We show that high-fidelity quantum state inversion is possible in a system of quantum dots with a 15~meV range of optical transition energies using a single broadband, chirped laser pulse, laying the foundation for high-bandwidth, multiplexed quantum networks

Design and characterization of quantum dot photonic crystal lasers

Quantum dot photonic crystal lasers are demonstrated at room temperature by optical pulse pumping. Coupled cavities were designed based on square lattice PC slabs. Optimized two-dimensional photonic crystal cavities were defined in 200nm slabs with five-stacked InAS QDs layers. The two- and four-coupled cavities showed as incident pump power threshold as 120μW and 370μW, respectively, both from QD ground state emission range. Both clear threshold in pump power-output resonance power and resonance line width narrowing were observed from our membrane samples. The measured wavelengths matched very well with wavelengths predicted by 3D-Finite Difference Time Domain modelling

Photonic crystal nanocavities with quantum well or quantum dot active material

We have investigated the miniaturization of photonic devices for ultimate photon localization, and have demonstrated two-dimensional photonic crystal nanolasers with two important quantum nanostructures-quantum wells (QWs) and quantum dots (QDs). Photonic crystal cavities with QW active material, are simple, but powerful nanolasers to produce intense laser output for signal processing. On the other hand, when located in a high-quality factor (Q) nanocavity, because QD(s) strongly couple with the intense optical field, QD photonic crystal cavities are expected to be good experimental setups to study cavity quantum electrodynamics, in addition to high speed and compact laser sources. Our photonic crystal nanolasers have shown as small thresholds as 0.12mW and 0.22mW for QD-photonic crystal lasers and QW-photonic crystal lasers, respectively, by proper cavity designs and nanofabrication. For QD-photonic crystal lasers, whispering gallery modes in square lattice were used together with coupled cavity designs and, for QW-photonic crystal lasers, quadrapole modes in triangular lattice with fractional edge dislocations were used to produce high-Q modes with small mode volume

Low threshold microcavity light emitter

Disclosed is a low threshold vertical cavity surface emitter having a low refraction index confining layer (36) directly in the cavity spacer. This allows a ½ wavelength cavity spacer and lateral size of as low as 2 &mgr;m. Also disclosed is a method of rapid temperature annealing to seal a III-V crystal and inhibit oxidative degradation.Board of Regents, University of Texas Syste

Threshold Temperature Dependence Of A Quantum-Dot Laser Diode With And Without P-Doping

A study of the threshold characteristics of quantum-dot (QD) laser diodes shows how inhomogeneous broadening and p-doping influence the QD laser\u27s temperature dependence of threshold To. The analysis includes the additional parameters of homogeneous broadening, quantum state populations, and threshold gain. The results show that while the source of negative To can occur due to different effects, the transparency current plays a critical role in both undoped and p-doped QD lasers. Experimental trends of negative To and their dependence on p-doping are replicated in the calculated results. Inhomogeneous broadening is found to play a lesser role to the transparency current in setting To. Homogeneous broadening is most important for uniform QDs with thermally isolated ground-state transitions. © 2009 IEEE

Transparency Current Influence On The Temperature Dependent Threshold Of Undoped And P-Doped Qd Laser Diodes

We show that the transparency current plays a central role in setting the temperature dependence of both undoped and p-doped quantum dot lasers. The influence of inhomogeneous broadening is also analyzed and shown to influence. © 2009 IEEE

Advanced Vcsel Technology: Self-Heating And Intrinsic Modulation Response

Experimental data and modeling results are presented for a new type of vertical-cavity surface-emitting laser (VCSEL) that solves numerous problems with oxide VCSELs. In addition, the new oxide-free VCSEL can be scaled to small size. Modeling shows that this small size can dramatically increase the speed of the laser through control of self-heating. Modeling compared with both the oxide and the new oxide-free VCSEL predict intrinsic modulation speed for room temperature approaching 80 GHz, indicating the potential for \u3e 100-Gb/s data speed from directly modulated VCSELs. The modeling is one of if not the first to include self-heating and spectral detuning between the gain and the cavity resonance that results from self-heating. The modeling results accurately accounts for the saturation in modulation speed in very high-speed oxide VCSELs operating at high temperature and accounts for the temperature of differential gain and photon density in limiting speed. Saturation of the photon density is found to limit the ultimate intrinsic speed. Differential gain decreases with increasing temperature but with sufficiently weak temperature dependence that it is not found to limit the VCSEL speed