Investigation of Nitrogen Induced Closely Coupled Sb Based Quantum Dots for Infrared Sensors Application
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0959-M16-07
Investigation of Nitrogen Induced Closely Coupled Sb Based Quantum Dots for Infrared Sensors Application Seongsin M. Kim, Fariba Hatami, Homan B. Yuen, and James S. Harris Stanford University, Stanford, CA, 94305 ABSTRACT We report the growth and structural properties of InSb and InSb:N quantum dots on InAs and GaAs substrates. Strain induced, self-assembled quantum dots are grown using solid-source molecular beam epitaxy. For improved growth control, we developed a growth technique similar to atomic layer epitaxy methods. InSb and InSb:N multiple quantum dots formed on both InAs and GaAs. We explain the formation of multiple quantum dots by the anisotropic distribution of strain energy within the quantum dot, the long adatom lifetime during atomic layer epitaxy, and the low bond energy of InSb. Nitrogen incorporation during formation of quantum dots changes the surface energy barrier and causes an anisotropic distribution of strain energy, results in the formation of closely coupled multiple quantum dots in the orientation. We obtained mid infrared luminescence around 3.6 µm from InNSb QDs grown on InAs substrate, where it exhibits relatively low nitrogen incorporation efficiencies compared to the quantum well structure. INTRODUCTION Nanophotonics plays a major role in the development of smart sensors, which require integrated functionality in order to achieve multiple chemical and biological agent detection, simultaneous identification, and real time information transfer. Most bi-molecules and biological agents based on proteins have strong absorption and resonance fingerprints between the mid- and far-infrared wavelength range of 3um and 15um. Therefore highly efficient, and inexpensive infrared (IR) sources and detectors are essential to smart sensor systems. Quantum dot lasers, which have been in development for decades, have several important advantages:[1-3] (1) low power consumption due to low threshold current operation, (2) array operation and integration due to low voltage and low current operation, (3) large wavelength tuning due to broad gain spectrum, (4) low cost due to simple growth and fabrication techniques. However, there has been a lack of development of IR quantum dot lasers, mainly due to the limited availability of material systems that can yield operating in the IR spectrum. Recent, newly-developed III-V dilute nitride materials have interesting physical properties which may enable MIR and FIR devices. The addition of small amounts of nitrogen into III-V semiconductors dramatically increases the wavelength due to the unique band interactions between nitrogen and its host material. Incorporating nitrogen into narrow-gap materials is very attractive because it can reduce the energy gap and enable emission beyond the FIR, a feat not possible with conventional III-V semiconductors. In addition, nitrogen in these materials will increase the electron effective mass, thus suppressing a auger recombination.
InSb, with an energy gap of 0.17 eV (7.3 µm), is the narrowest gap III-V semico
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