Preparation of GaN/Porous silicon heterojunction photodetector by laser deposition technique
Makram A. Fakhri, Haneen D. Jabbar, Mohammed Jalal AbdulRazzaq, Evan T. Salim, Ahmad S. Azzahrani, Raed Khalid Ibrahim, Raid A. Ismail
Abstract
Abstract In this work, gallium nitride (GaN) thin film was deposited on porous silicon (PSi) substrate via a pulsed laser deposition route with a 355 nm laser wavelength, 900 mJ of laser energy, and various substrate temperatures raging from 200 to 400 °C. The structural and optical properties of GaN films as a function of substrate temperature are investigate. XRD studies reveal that the GaN films deposited on porous silicon are nanocrystalline with a hexagonal wurtzite structure along (002) plane. The photoluminescence emission peaks of the GaN/PSi prepared at 300 °C substrate temperature are located at 368 nm and 728 nm corresponding to energy gap of 3.36 eV and 1.7 eV, respectively. The GaN/PSi heterojunction photodetector prepared at 300 °C exhibits the maximum performance, with a responsivity of 29.03 AW −1 , detectivity of 8.6 × 10 12 Jones, and an external quantum efficiency of 97.2% at 370 nm. Similarly, at 575 nm, the responsivity is 19.86 AW −1 , detectivity is 8.9 × 10 12 Jones, and the external quantum efficiency is 50.89%. Furthermore, the photodetector prepared at a temperature of 300 °C demonstrates a switching characteristic where the rise time and fall time are measured to be 363 and 711 μs, respectively.