论文标题
在封闭的半导体微腔中抑制表面相关的损失
Suppression of surface-related loss in a gated semiconductor microcavity
论文作者
论文摘要
我们提出了一种表面钝化方法，该方法将与高度微型GAAS开放的微腔中降低了与表面相关的损失近两个数量级。微腔由弯曲的介电分布式bragg反射器（DBR）组成，半径$ \ sim 10 $ $ $ $ $ m与基于GAAS的异质结构配对。异质结构由半导体DBR组成，然后是N-I-P二极管，并在内在区域具有一层量子点。高度掺杂的N-和P层中的自由载体吸收通过将它们定位在真空电磁场的节点附近，从而最大程度地减少它们。然而，表面位于真空场的抗节点上，并导致明显的损失。这些损失通过表面钝化大大降低。对波长的强烈依赖性意味着表面钝化的主要作用是消除表面电场，从而通过类似Franz-keldysh样效应来消除散gap的吸收以下。另一个好处是，表面钝化减少了GAAS表面的散射。这些结果在其他依赖于GAAS-VACUUM界面限制电磁场的纳米光子设备中很重要。
We present a surface passivation method that reduces surface-related losses by almost two orders of magnitude in a highly miniaturized GaAs open microcavity. The microcavity consists of a curved dielectric distributed Bragg reflector (DBR) with radius $\sim 10$ $μ$m paired with a GaAs-based heterostructure. The heterostructure consists of a semiconductor DBR followed by an n-i-p diode with a layer of quantum dots in the intrinsic region. Free-carrier absorption in the highly doped n- and p-layers is minimized by positioning them close to a node of the vacuum electromagnetic-field. The surface, however, resides at an anti-node of the vacuum field and results in significant loss. These losses are much reduced by surface passivation. The strong dependence on wavelength implies that the main effect of the surface passivation is to eliminate the surface electric field, thereby quenching below-bandgap absorption via a Franz-Keldysh-like effect. An additional benefit is that the surface passivation reduces scattering at the GaAs surface. These results are important in other nano-photonic devices which rely on a GaAs-vacuum interface to confine the electromagnetic field.
