Hybrid Quantum Dot-2D Electron Gas Devices for Coherent Optoelectronics

Abstract

We present an inverted GaAs 2D electron gas with self-assembled InAs quantum dots in close proximity, with the goal of combining quantum transport with quantum optics experiments. We have grown and characterized several wafers -using transport, AFM and optics -finding narrowlinewidth optical dots and high-mobility, single subband 2D gases. Despite being buried 500 nm below the surface, the dots are clearly visible on AFM scans, allowing precise localization and paving the way towards a hybrid quantum system integrating optical dots with surface gate-defined nanostructures in the 2D gas.

Optically Loaded Semiconductor Quantum Memory Register

“…Having the SAQD layer closer to the QW would increase capacitive coupling but at the cost of mobility. In previous reports mobilities as high as 0.5 × 10 6 cm 2 /Vs were reported for a separation of 45 nm [40]. Our device here proposes a shorter separation of 20 to 30 nm.…”

“…Early efforts were motivated by the possibility of creating a transistor where the gate bias modified the mobility rather than the carrier density of the 2DEG. Thus, many experiments have investigated the influence of nearby SAQDs on the mobility of carriers in the 2DEG [37][38][39][40][41][42][43][44][45]. These experiments measure slight reductions in mobility due to the SAQDs, however values as high as 0.5 × 10 6 cm 2 /Vs are observed even in the presence of a SAQD layer 45 nm away [40].…”

“…Thus, many experiments have investigated the influence of nearby SAQDs on the mobility of carriers in the 2DEG [37][38][39][40][41][42][43][44][45]. These experiments measure slight reductions in mobility due to the SAQDs, however values as high as 0.5 × 10 6 cm 2 /Vs are observed even in the presence of a SAQD layer 45 nm away [40]. In fact, some groups have used the ability to controllably charge the SAQDs to explore the nature of the metal-insulator transition in the 2DEG [46][47][48][49].…”