This review covers a spectrum of optoelectronic properties of and uses for semi-insulating semiconductor heterostructures and thin films, including epilayers and quantum wells. Compensation by doping, implantation, and nonstoichiometric growth are described in terms of the properties of point defects and Fermi level stabilization and pinning. The principal optical and optoelectronic properties of semi-insulating epilayers and heterostructures, such as excitonic electroabsorption of quantum-confined excitons, are described, in addition to optical absorption by metallic or semimetallic precipitates in these layers. Low-temperature grown quantum wells that have an arsenic-rich nonstoichiometry and a supersaturated concentration of grown-in vacancies are discussed. These heterostructures experience transient enhanced diffusion and superlattice disordering. The review discusses the performance of optoelectronic heterostructures and microcavities that contain semi-insulating layers, such as buried heterostructure stripe lasers, vertical cavity surface emitting lasers, and optical electroabsorption modulators. Short time-scale applications arise from the ultrashort carrier lifetimes in semi-insulating materials, such as in photoconductors for terahertz generation, and in saturable absorbers for mode-locking solid state lasers. This review also comprehensively describes the properties and applications of photorefractive heterostructures. The low dark-carrier concentrations of semi-insulating heterostructures make these materials highly sensitive as dynamic holographic thin films that are useful for adaptive optics applications. The high mobilities of free carriers in photorefractive heterostructures produce fast dielectric relaxation rates that allow light-induced space-charge gratings to adapt to rapidly varying optical fringe patterns, canceling out environmental noise during interferometric detection in laser-based ultrasound, and in optical coherence tomography. They are also the functional layers in high-sensitivity dynamic holographic materials that replace static holograms in Fourier imaging systems and in experimental Tbit/s optical systems. Semi-insulating heterostructures and their applications have attained a degree of maturity, but many critical materials science issues remain unexplored.

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Semi-insulating semiconductor heterostructures: Optoelectronic properties and applications

Selective growth of AlxGa1−xAs embedded in etched grooves on GaAs by low-pressure OMVPE

An effective device structure for reducing leakage current in buried heterostructure laser diodes with semi-insulating InP blocking layers is analyzed. The analysis utilizes a semiconductor device simulator in which deep trap levels are taken into account. It predicts that the addition of a thin wide-bandgap InGaP layer in the semi-insulating region at the mesa boundaries as a barrier to prevent double injection into the semi-insulating region is effective in reducing leakage current. >

Analysis of leakage current in buried heterostructure lasers with semiinsulating blocking layers

We used metalorganic chemical vapor deposition to fabricate a planar‐embedded InGaAsP/InP heterostructure laser with a semi‐insulating InP current‐blocking layer The laser exhibits cw operation with a low, 20 mA threshold current and a high external differential quantum efficiency of 40% at room temperature Measurements have also shown a small‐signal frequency response of 10 GHz due to an extremely small parasitic capacitance of 35 pF

Planar‐embedded InGaAsP/InP heterostructure laser with a semi‐insulating InP current‐blocking layer grown by metalorganic chemical vapor deposition

GaInAs/InP planar buried heterostructure (PBH) lasers with semi-insulating blocking layers were grown in an `all? atmospheric OMVPE system. These layers had current thresholds as low as 35 mA and differential quantum efficiencies of ?16% at a wavelength of 1.64 ?m. The maximum power output was 80 mW pulsed and 8mWCW.

Planar buried heterostructure InP/GaInAs lasers grown entirely by OMVPE

A new structure semi‐insulator‐embedded flat‐surface buried heterostructure 1.3 μm InGaAsP/InP laser has been developed using chloride vapor phase epitaxy. cw threshold currents as low as 18 mA and high‐temperature cw operation up to 100 °C have been obtained. Small‐signal response above 4 GHz has been achieved and no remarkable roll‐off has been observed, which is due to small parasitic capacitance.

S. Yamakoshi

Papers

Semi‐insulator‐embedded InGaAsP/InP flat‐surface buried heterostructure laser