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A transparent indium tin oxide (ITO) contact to bulk n-GaN and n-GaN thin film on c-face sapphire with a specific contact resistivity of 8.06 × 10⁻⁴Ω.cm²and 3.71 × 10⁻⁴Ω.cm²was measured, respectively. Our studies relied on an RF sputtering system for ITO deposition. We have investigated the formation of the ITO-based contacts on untreated and plasma treated samples. A nonlinearI–Vcurve was observed for ITO deposited on untreated samples. On the other hand, anI–Vcurve with linear behavior was observed for plasma-treated samples, indicating the formation of ohmic contacts. From theC-Vmeasurements, it was observed that there was also an increase in the carrier concentration in plasma treated samples compared to untreated samples. This can be attributed to the removal of surface oxide layer present on the GaN surface, and increase in nitrogen vacancies after SiCl₄plasma treatment. In addition, the increase in nitrogen vacancies at the GaN surface can also enhance localized surface/sub-surface carriers, thereby reducing the contact resistance further.

 

Optical stretcher is a tool in which two counter-propagating, slightly diverging, and identical laser beams are used to trap and axially stretch microparticles in the path of light. In this work, we utilized the dual-beam optical stretcher setup to trap and stretch human embryonic kidney (HEK) cells and mammalian breast cancer (MBC) cells. Experiments were performed by exposing the HEK cells to counter-propagating laser beams for 30 seconds at powers ranging from 100 mW to 561 mW. It was observed that the percentage of cell deformation increased from 16.7% at 100 mW to 40.5% at 561 mW optical power. The MBC cells exhibited significantly higher cell stretching compared to HEK cells at the same power (80 mW). Moreover, the minimum trapping power in HEK cells was 80.5mW as compared to 65.2mW in MBC cells. This study provides useful insights into the characterization of cytoskeletal elasticity in different cell types based on non-contact optical cell stretching.