Laser diodes in piezoelectric quantum-well structures

Cooper, Catherine; Westwood, D.I.; Blood, P.

doi:10.1063/1.117655

Cited by 11 publications

(4 citation statements)

References 3 publications

(3 reference statements)

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“…must hold and can be checked by calculating the η 1 dependence of e 14 and the η 4 dependence of e 11 . In this case, no correction is required and the linear slopes of these dependences give the proper second-order coefficients, and they must be equal.…”

Section: Reduction Of the Number Of Calculation And Consistency Chmentioning

confidence: 99%

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First- and second-order piezoelectricity in III-V semiconductors

2011

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We present the results of first-principles plane-wave pseudopotential calculations of piezoelectric coefficients of first and second order for a total of nine III-V binary phases (AlP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs, InSb) of zinc-blende semiconductors. These coefficients are used to calculate the piezoelectric fields for [111]-oriented quantum wells (QWs) with different well-barrier combinations and various dimensions. We derive an approximate analytic expression for the strain tensor in the case of pseudomorphic growth along an arbitrary growth direction. Together with the piezoelectric coefficients, this allows a simple calculation of the piezoelectric field up to second order in strain for an arbitrary growth direction and any material combination within the nine III-Vs presented here. Nonlinear contributions to the polarization are shown to be of significant magnitude for all the materials presented. In some cases the field is increased by the second-order terms; in some cases it is decreased. We analyze the chemical trends of the obtained coefficients. We compare our results to available experiments and find good agreement in one-third of the cases, while for the remaining cases the calculated field is larger to significantly larger than in the measurements. We discuss the popular experimental techniques and highlight possible reasons for the discrepancies.

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Section: Reduction Of the Number Of Calculation And Consistency Chmentioning

confidence: 99%

“…8 and 9), quantum wells (QWs) (e.g., Refs. [10][11][12], quantum wires (e.g., Refs. [13][14][15], and quantum dots (e.g., Refs.…”

Section: Introductionmentioning

confidence: 99%

First- and second-order piezoelectricity in III-V semiconductors

2011

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“…In fact, the importance of piezoelectric fields in III-V semiconductors has first been recognized for cubic zincblende heterostructures grown on a (111) plane [7]. The characteristics of such structures and some novel device applications have been discussed in detail [8] [9] [10]. On the other hand, AlN has long been known as a strongly piezoelectric, though insulating material.…”

Section: Introductionmentioning

confidence: 99%

The role of piezoelectric fields in GaN-based quantum wells

Hangleiter

Kollmer

et al. 1998

MRS Internet j. nitride semicond. res.

144

109

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In this contribution, we focus on the consequences of the piezoelectric field, which is an inherent consequence of the commonly used wurtzite phase of GaN, on the optical properties of strained GaN-based quantum well structures. We demonstrate that both in GaN/AlGaN and in GaInN/GaN single quantum well structures, the piezoelectric field leads to a Stark-shift of the fundamental optical transitions, which can lead to luminescence emission far below the bulk bandgap. Due to the spatial separation of the electron and hole wavefunctions in such structures, the oscillator strength of these transitions may become extremely small, many orders of magnitude lower than in the field-free case. From specially designed structures, we can even determine the sign of the piezoelectric field and relate it to the polarity of the layers. Under high-excitation conditions, as found in a laser diode, the piezoelectric field is almost completely screened by the injected carriers. As a consequence, the stimulated emission is significantly blue-shifted compared to the photoluminescence, which has sometimes been confused with localization effects.

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“…Both approaches exploit the modi¢cation of subband structure and wavefunction character in tailored wells. Some work has also been done on the use of well-shaping in bipolar lasers by strategic delta-doping [10], the piezoelectric e¡ect [11] and the use of asymmetric dual quantum wells [12], aimed at producing enhanced functionality, such as wide range tunability. However, in recent theoretical work [13], it has been shown that combining strain with appropriately shaped steppedalloy QWs can lead to improvements in commonly used ¢gures of merit, notably threshold current performance, in bipolar diode lasers.…”

Section: Introductionmentioning

confidence: 99%

Reduced Threshold Current in Bipolar Diode Lasers by Non-square Quantum Well Growth

et al. 2003

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By device simulation, it is shown that non-square quantum well growth (well shaping) provides a means for reducing the threshold current of bipolar quantum well diode lasers. Calculations of subband structure, optical matrix elements and laser gain are performed based on a 4-band (electron, heavy-hole, light-hole, split-off-hole) Hamiltonian with Burt-Foreman Hermitianization. A non-optimized, compressively strained, InGaAs-AlGaAs (on GaAs) shaped well laser, operating at 0.97 µm is predicted to show improvements in both radiative and non-radiative current performance compared to a device based on an optimal square quantum well of the same well width and emission wavelength. These improvements result from modification of subband structure giving greater subband separation in the shaped well than in the square well.

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Laser diodes in piezoelectric quantum-well structures

Cited by 11 publications

References 3 publications

First- and second-order piezoelectricity in III-V semiconductors

First- and second-order piezoelectricity in III-V semiconductors

The role of piezoelectric fields in GaN-based quantum wells

Reduced Threshold Current in Bipolar Diode Lasers by Non-square Quantum Well Growth

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