Built-in field control in alloyedc-plane III-N quantum dots and wells

Abstract

Access to the full text of the published version may require a subscription. We investigate the degree to which the built-in electric field can be suppressed by employing polarization-matched barriers in III-N quantum well and dot structures grown along the c axis. Our results show that it is possible to take advantage of the opposite contributions to the built-in potential arising from the different possible combinations of wurtzite GaN, InN, and AlN when alloying the materials. We show that, for a fixed bandgap of the dot/well, optimal alloy compositions can be found that minimize the built-in field across the structure. We discuss and study the impact of different material parameters on the results, including the influence of nonlinear effects in the piezoelectric polarization. Structures grown with unstrained barriers and on GaN epilayers are considered, including discussion of the effects of constraints such as strain limits and alloy miscibility. Rights

Polarization Matching in AlGaN-Based Multiple-Quantum-Well Deep Ultraviolet Laser Diodes on AlN Substrates Using Quaternary AlInGaN Barriers

“…11), and provide no electrical confinement. It may be possible to design polarization charge free active regions using quaternaries for both QWBs and QWs [30]; yet, this approach poses greater challenges for crystal growth.…”

“…So far, different methods have been proposed to improve this overlap, and reduce or completely eliminate the related quantum-confined Stark effect (QCSE) [18]. Various strain relaxation methods [26]- [30] have been used to minimize the piezoelectric part of polarization charge. However, reduction of compressive strain in AlGaN-based active regions may enhance coupling to TM optical modes [19], [31], [32], and lead to higher losses.…”

Atomistic analysis of the impact of alloy and well-width fluctuations on the electronic and optical properties of InGaN/GaN quantum wells

“…Several features are clearly visible. To a first approximation, the different components reflect the profile one would expect from a continuum-based description [54]. However, even when averaging the strain tensor components over the supercell, the impact of local alloy fluctuations giving rise to local strain tensor fluctuations is clearly visible.…”

Tight‐binding model for the electronic and optical properties of nitride‐based quantum dots

“…Unfortunately, as discussed for example in detail in Ref. [19], composition and strain dependence of several critical parameters are not well known. Therefore, further theoretical and experimental effort is required to reduce the uncertainty in these values.…”