Hot electron light emission and lasing in semiconductor heterostructure (Hellish) devices are surface emitters the operation of which is based on the longitudinal injection of electrons and holes in the active region These devices can be designed to be used as vertical cavity surface emitting laser or, as in this study, as a vertical cavity semiconductor optical amplifier (VCSOA) This study investigates the prospects for a Hellish VCSOA based on GaInNAs/GaAs material for operation in the 13-μm wavelength range Hellish VCSOAs have increased functionality, and use undoped distributed Bragg reflectors; and this coupled with direct injection into the active region is expected to yield improvements in the gain and bandwidth The design of the Hellish VCSOA is based on the transfer matrix method and the optical field distribution within the structure, where the determination of the position of quantum wells is crucial A full assessment of Hellish VCSOAs has been performed in a device with eleven layers of Ga035In065N002As008/GaAs quantum wells (QWs) in the active region It was characterised through I-V, L-V and by spectral photoluminescence, electroluminescence and electro-photoluminescence as a function of temperature and applied bias Cavity resonance and gain peak curves have been calculated at different temperatures Good agreement between experimental and theoretical results has been obtained

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GaInNAs-based Hellish-vertical cavity semiconductor optical amplifier for 1.3 μm operation

Hot electron light emitting and laser semiconductor heterostructure (HELLISH-1) is a novel surface emitting device. It utilizes longitudinal transport where electric fields heat up electrons and holes in their respective channels simultaneously. Hot electrons and holes are then captured by mainly tunnelling and thermionic emission in the quantum well where radiative recombination occurs. In this work, we demonstrate and compare the operation of HELLISH-1 and ultrabright HELLISH-1 (UB-HELLISH-1). The latter is an improved version of HELLISH-1 which incorporates a distributed Bragg reflector allowing detection of super radiant emission with a vastly improved full width at half-maximum. It is also shown that the emitted light intensity in the UB-HELLISH-1 device is enhanced by about two orders of magnitude compared with the simple structure.

Ultra bright surface emission from a distributed Bragg reflector hot electron light emitter

Several novel laterally biased HELLISH (hot electron light emission and lasing in semiconductor heterostructure) devices have previously been reported and demonstrated. These light emitting devices are normally operated at high applied fields to heat carriers to a point where they can transfer into the quantum well via tunnelling or thermionic emission. However, it has been observed that, in most devices, light emission occurs at relatively low applied fields. In this region, the fields are too low for significant heating of carriers. Therefore, the mechanism for light emission in this region cannot be explained by hot electron effects. The results illustrating the low field operation of HELLISH devices are presented together with a quasi-flat-band model.

Low field operation of hot electron light emitting devices: quasi-flat-band model

The hot electron light emitting and lasing semiconductor heterostructure vertical cavity surface emitting lasers (VCSELs) are devices that utilise hot carrier transport parallel to the layers of the GaxAl1 xAs p‐n junction. The junction contains a GaAs quantum well (QW) in the depletion region. The fabrication of these devices is very simple, and requires only two top contacts that are diffused throughout the heterolayers. Light emission, being a hot carrier effect, is independent of the polarity of the applied bias. Pulsed operation of the device as a VCSEL has already been demonstrated at room temperature. An output power of 5.5 mW in a single longitudinal mode has been obtained. The doping and other structural parameters can be optimised for efficient injection of hot electron‐hole pairs into the QW. In this work, we report our reflectivity, electroluminescence, and photoluminescence studies at room temperature. We also present the experimental results of emitted power measured as a function of the applied electric field. © 2000 Elsevier Science S.A. All rights reserved.

VCSEL structure hot electron light emitter

The basic operation of a novel GaInNAs/GaAs based light emitting/absorbing device operating at 1250 nm is described. The device is a bi-directional field effect light emitting and absorbing heterojunction (BiFEEAH), which can simultaneously emit and detect light. This feature makes it possible to construct a wavelength converter, where one end of the device absorbs incoming light and the other end emits light at a different wavelength. The current device consists of a simple GaAs p-i-n structure, containing a single 90 /spl Aring/ GaInNAs quantum well in its intrinsic region. This is fabricated into a four contact device with separate n and p conducting channels.

R. Gupta

Papers

Hot electron light-emitting and lasing semiconductor heterostructures--type 1