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The recent exploration of porous Germanium (PGe) techniques marks a significant advancement in the scalable production of detachable Ge membranes and devices. However, there is a notable gap in the comprehensive understanding of the critical factors necessary to control the adhesion strength of these nanomembranes. This study delves into the effects of Ge growth temperature, in-situ annealing processes, and the thickness of the PGe layer on the reorganization of the porous interlayer, subsequently influencing the properties of the separation layer. We particularly focus on how adjusting these parameters can fine-tune the adhesion strength of the epitaxial layer, ranging from a freestanding state to a fully bonded nanomembrane. A key finding is that the thermal budget experienced by the porous structure during the buffer layer's growth significantly affects the nanomembrane's adhesion characteristics; it is imperative to minimize this duration, especially at higher growth temperatures. Our research demonstrates that by precisely controlling the voids within the PGe layer, the adhesion strength can be effectively modulated through variations in the PGe layer's thickness. The outcomes of this study offer crucial insights into the controllable adhesion strength of Ge nanomembranes, paving the way for the targeted development of detachable devices. [Display omitted] • Tuning of the Ge membrane adhesion strength by adjusting growth and porous parameters. • Creation of a detachable Germanium membrane using a porous substrate. • Controlling the morphological reorganization of the Ge porous structure. [ABSTRACT FROM AUTHOR]

• Comprehensive investigation of porous germanium reorganization. • Investigation on the effect of Porosity, thickness, temperature, and duration. • Proof of feasibility of suspended Ge foil for the growth of detachable devices. • Reorganization of porous germanium toward a detachable membrane. Porous germanium (PGe) substrates have recently attracted significant attention for the development of lightweight and flexible solar cells and optoelectronic devices. A reliable approach for releasing epitaxial layers based on Germanium and reusing the substrate involves utilizing a bilayer structure of PGe. The growth of such detachable devices holds great potential for integration onto the Si platform. The used structure of PGe is made of a low-porosity layer serving as epitaxial seed on top of high-porosity one used as a weak separation layer. In this work, we investigate the impact of thermal annealing on the PGe morphology for deeper understanding of the mechanisms involved in the formation of the epitaxial seed layer and the voided weak layer underneath. Indeed, thermal-induced reconstruction has been investigated at various annealing temperatures and times for PGe layers with differing porosity levels, encompassing low, high, and gradual porosity profiles. Our findings reveal the formation of a modified substrate at low annealing temperatures, resulting in a suspended membrane on top of the fragile separation layer, rendering it suitable for detachment and subsequent substrate reuse. [ABSTRACT FROM AUTHOR]