High-temperature quasi-continuous operation of optically pumped CdZnTe/ZnTe multiple-quantum-well lasers at 620 nm
Low-lasing-threshold quasi-continuous optically pumped II-VI quantum-well lasers were operated well above room temperature at 620 nm. This result shows promise for high-repetition-rate, short-pulse generation by direct modulation of the injection current and also CW operation of future wide-gap II-VI diode lasers above room temperature.<<ETX>>
Optoelectronic properties of n-type CdZnTe 2-DEG single-quantum-well heterostructures
Optoelectronic properties of asymmetrically strained II-VI CdZnTe single-quantum-well structures grown by molecular-beam epitaxy are reported. Indium doping CdZnTe n-type using a two-dimensional electron gas heterostructure achieved a carrier mobility of 5000 cm/sup 2//spl middot/V/sup -1/ s/sup -1/ at 40 K. A shallow donor ionization energy of 14.5 meV was determined from Hall effect measurements. Fabrication of a large-area-mesa heterostructure device allowed us to investigate exciton absorption of the mixed type-I and type-II single quantum well. Control of the electron concentration in the quantum well allows optical absorption modulation using both the quantum-confined Stark effect (QCSE) and phase-space absorption quenching. Separation of electron and hole photocurrents in different layers is demonstrated and results in photogain. A heavy-hole red-shift of 9.9 meV/V due to the reverse QCSE is reported.
Points of strong summability of Fourier series
In this paper we present a new solution of Hardy and Littlewood's problem concerning strong summability of Fourier series; we also present a property of points of strong summability.