US 6,870,178 B2 · Semiconductor laser with reduced temperature sensitivity

Abstract

A quantum dot (QD) laser having greatly reduced temperature sensitivity employs resonant tunnel-injection of carriers into the QDs from a pair of quantum wells (QWs). The carriers are injected through barrier layers. Because the tunnel-injection process is essentially temperature-independent, and because the tunnel-injection of carriers is the dominant source of current through the device, temperature-dependent currents are virtually eliminated, resulting in a device having a temperature-independent threshold current. In an additional device, carriers are injected into QDs from a pair of optical confinement layers (OCLs), either by tunnelling or thermionic emission. Each barrier layer is designed to have a low barrier height for carriers entering the QDs, and a high barrier height for carriers exiting the QDs. As a result, parasitic current from carriers leaving the QDs is greatly reduced, which enables the device to have low temperature sensitivity even without using resonant tunnel-injection and/or QWs.

Claims25

Dependent claims

A semiconductor structure, comprising:

a first barrier layer having a first barrier thickness;
a second barrier layer having a second barrier thickness;
a quantum dot layer including at least one quantum dot, the quantum dot layer being disposed between the first and second barrier layers;
a first quantum well layer, the first barrier layer being disposed between the first quantum well layer and the quantum dot layer, and the first barrier thickness being sufficiently small to enable electrons to tunnel from the first quantum well layer to the quantum dot layer;
and
a second quantum well layer, the second barrier layer being disposed between the second quantum well layer and the quantum dot layer, and the second barrier thickness being sufficiently small to enable holes to tunnel from the second quantum well layer to the quantum dot layer.

3 more elements

A semiconductor structure, comprising:

a first barrier layer;
a second barrier layer;
a quantum dot layer including at least one quantum dot, the quantum dot layer being disposed between the first and second barrier layers;
an n-side optical confinement layer, the first barrier layer being disposed between the n-side optical confinement layer and the quantum dot layer, the first barrier layer having an amount of transparency for electrons being transported from the n-side optical confinement layer to the quantum dot layer through the first barrier layer, and the first barrier layer having an amount of transparency for holes being transported from the quantum dot layer to the n-side optical confinement layer through the first barrier layer;
and
a p-side optical confinement layer, the second barrier layer being disposed between the p-side optical confinement layer and the quantum dot layer, the second barrier layer having an amount of transparency for holes being transported from the p-side optical confinement layer to the quantum dot layer through the second barrier layer, and the second barrier layer having an amount of transparency for electrons being transported from the quantum dot layer to the p-side optical confinement layer through the second barrier layer, wherein the amount of transparency for electrons being transported from the n-side optical confinement layer to the quantum dot layer through the first barrier layer is greater than the amount of transparency for electrons being transported from the quantum dot layer to the p-side optical confinement layer through the second barrier layer, and the amount of transparency for holes being transported from the p-side optical confinement layer to the quantum dot layer through the second barrier layer is greater than the amount of transparency for holes being transported from the quantum dot layer to the n-side optical confinement layer through the first barrier layer.

3 more elements

Dependencies are inferred from the claim text.

Semiconductor laser with reduced temperature sensitivity

Life of this patent

Semiconductor laser with reduced temperature sensitivity

Life of this patent

Abstract

Claims25