C71.00425. Charge Carrier Transport in Cuprous Oxide: A Puzzle
Presented by: Garima Aggarwal
Deciphering the carrier transport mechanism in Cu2O has been elusive, as none of the classical scattering mechanisms seems to be operative. Towards this, we study electrical properties of Cu2O, wherein samples are prepared via thermal oxidation (TO), pulsed laser deposition (PLD), and electrodeposition. These methods provide a large range of grain sizes (100nm to 5mm), type of grain boundaries (high & low angle), and intrinsic defect concentration (1013 to 1018 cm−3). T dependent Hall measurement is used to study carrier concentration and hole mobility. We observe the presence of two acceptor levels; a normal and a split Cu vacancy for the first time experimentally. The mobility vs. T data exhibits a maximum at 200 K for polycrystalline samples, while, monotonically decreases for single crystal and textured PLD thin film in the entire T range of study (80 – 300 K). Grain boundary (GB) scattering mechanism explains the dependence of transport at T < 200 K for samples with high angle GB. We find that trap mediated scattering is dominant for single crystal and poly-crystal at T > 200 K. This suggests that instead of increasing grain size or doping, the neutralization of trap centres is the only possible way to increase the mobility and thereby, performance of Cu2O based devices.
- Garima Aggarwal
- Sandeep K. Maurya
- K. R. Balasubramaniam