Aditya Jain

My current interests are in electrical and thermal transport measurements in disordered two-dimensional electron systems based on GaAs/AlGaAs heterostructures. The general observables in thermal transport measurements are thermopower ‘S’ and thermal conductivity ‘λ’. When a temperature gradient is set up across the two ends of an electronic system (metal/semiconductor), a potential difference can be observed at the two ends. The ratio of the potential difference to the temperature difference is known as the thermopower of the specimen (S=V_th/∆T). Generally, the observed thermopower is the combined signal of two different contributions electron diffusion (S^d = const ×T) and phonon drag (S^g). My preliminary aim is to suppress the contribution from phonon drag for a reasonably large window of temperatures and enhance the possibility of observing thermopower from the electron diffusion process. This will also help using linear behavior of S^d with T, as a thermometer for thermal transport measurements. My ultimate goal is to realize the many-body localized phase in disordered two-dimensional electron/hole system by suppressing the e-p coupling (suppressing the phonon drag).

During my Ph.D., I have worked in the area of magneto-transport in cryogenic temperatures       (~300 milliKelvin) and low-frequency noise measurements in mesoscopic devices. I have studied the effect of the ionic liquid gate on low-frequency conductivity noise in RF sputtered Ga doped ZnO thin films. I have also done some noise measurement (Hooge’s parameter and noise) on MBE grown GaAs/AlGaAs heterostructure.

I studied the effect of (superconductivity induced) invasive voltage probes on magneto-transport properties on the GaN thin films of different mobilities, compared to the non-invasive probes to discriminate the anomalous effects arising due to the invasive nature of the probes.

As part of my research work, I have extensively used class 10k clean room device fabrication facility of the department of physics at IIT Bombay. Which is equipped with,  mask aligner for photolithography, thermal evaporators (metallization: making Ohmic and Schottky contacts at P mbar), stylus profilometer and Atomic Force Microscope (etch depth, height, surface profile analysis), wafer scriber (precise cleaving of sample, mechanical etching), rapid thermal annealer (annealing in the inert and reducing environment), RF/DC/Microwave plasma cleaning (for cleaning surfaces etc.)