Spin qubit in semiconductor quantum dot arrays offers a promising platform for future scalable quantum computing with its small size and compatibility with modern semiconductor industry. To scale up the quantum dot arrays, one of the major challenges is the wiring bottleneck, as a high density of control lines might need to be integrated into a small chip. A proposal to solve this problem is using the shared control protocol, in which multiple qubits could be controlled by a shared line. For this, the most critical requirement is to realize uniformity across the quantum dot array, such that a single control signal could lead to an identical response in all dots involved. However, such uniformity is hard to achieve due to the variation of the device fabrication, and tackling this problem via materials and fabrication optimization only appears to be a daunting challenge.

In this thesis, we propose a potential solution to achieve uniformity of threshold voltage in such share-controlled systems. This solution is based on the hysteresis behavior of turn-on voltage in the heterostructure field-effect transistor (HFET) devices hosting the quantum dot array. In the Ge/SiGe HFET devices with hole as carrier, we found that the drift of turn-on voltage can be caused by population of 2DHG under negative gate voltage and reversed by applying positive gate voltage. We attribute this effect to trapping and detrapping processes on the dielectric surface of the device. Following this discovery, an automatic feedback control program was designed, in which gate voltage pulses are applied to control the trap filling level such that potential landscape in the device corresponds to the desired turn-on voltage. Using this program, we performed deeper investigations of the turn-on voltage shift including its relaxation and history-dependent stability. A hypothetical physical model for observations in these experiments is followed. For practical application of this effect, the feasibility to locally define and control the turn-on voltage is also demonstrated. Based on these results, we present a proposal for addressable manipulation of potential landscape in share-controlled quantum dot array, which might potentially realize the threshold voltage uniformity for scalable quantum dot array in the future.