- Logan Suchanec, Physics, University of Delaware
- Jamie Phillips, ECE, University of Delaware
- Abhilasha Kamboj, ECE, University of Delaware
Energy harvesting is of great significance to accessing sub-millimeter IOT systems. A photovoltaic (PV) is a semiconductor device that converts light into electricity. On exposure to light, a PV generates excited carriers and in turn, generates a voltage/current. Solar cells are one very common example of a PV. Power generation in the micro-scale systems with the sun as the source allows us to do a wide range of outdoor studies for eg: tracking the migration of Monarch butterflies. This project aims to characterize micro-scaled PVs in a controlled environment in the lab and outdoors under real-life conditions.
The photovoltaics consist of GaAs pn junction with AlGaAs layers acting as window and back-surface field layers to ensure maximum collection of excited carriers. The photovoltaics are first characterized in the lab where their photocurrents are measured using a Keithley 2401 source meter in a probe station. A visible lamp is used to illuminate the PVs. From the measurements, the critical parameters such as the open-circuit voltage (Voc), short-circuit current (Isc), fill factor (FF), and maximum power point (MPP) are measured.
Next, we focus on studying the PV that best mimics the setting when mounted on a butterfly i.e. outside in the daylight. A simple recreation of the laboratory setup was done with the PV to be angled toward the optimized incident sunlight angle to ensure the most sunlight comes into contact with the PV. The voltage-dependent current is studied throughout the day dependent on the conditions for eg: cloudy, sunny, temperature, time, etc.
The outdoor evaluation will help demonstrate the stability and practical use of the PVs once incorporated into the actual study.
Keywords: Photovoltaic cells, GaAs-AlGaAs semiconductors, Energy harvesting