Carrier diffusion in GaN -- a cathodoluminescence study. I: Temperature-dependent generation volume

Abstract

The determination of the carrier diffusion length of semiconductors such as GaN and GaAs by cathodoluminescence imaging requires accurate knowledge about the spatial distribution of generated carriers. To obtain the lateral distribution of generated carriers for sample temperatures between 10 and 300 K, we utilize cathodoluminescence intensity profiles measured across single quantum wells embedded in thick GaN and GaAs layers. Thin (Al,Ga)N and (Al,Ga)As barriers, respectively, prevent carriers diffusing in the GaN and GaAs layers to reach the well, which would broaden the profiles. The experimental cathodoluminescence profiles are found to be systematically wider than the energy loss distributions calculated by means of the Monte Carlo program CASINO, with the width monotonically increasing with decreasing temperature. This effect is observed for both GaN and GaAs and becomes more pronounced for higher acceleration voltages. We discuss this phenomenon in terms of both, the electron-phonon interaction controlling the energy relaxation of hot carriers, and the shape of the initial carrier distribution. Finally, we present a phenomenological approach to simulate the carrier generation volume that can be used for the investigation of the temperature dependence of carrier diffusion.

References in corpus (4)

• Stacking faults as quantum wells in nanowires: Density of states, oscillator strength and radiative efficiency
• Carrier diffusion in GaN -- a cathodoluminescence study. III: Nature of nonradiative recombination at threading dislocations
• Carrier diffusion in GaN -- a cathodoluminescence study. II: Ambipolar vs. exciton diffusion
• Electron-phonon relaxation and excited electron distribution in gallium nitride

Cited by in corpus (5)

• Carrier diffusion in GaN -- a cathodoluminescence study. III: Nature of nonradiative recombination at threading dislocations
• Optical and thermal characterization of a group-III nitride semiconductor membrane by microphotoluminescence spectroscopy and Raman thermometry
• Carrier diffusion in GaN -- a cathodoluminescence study. II: Ambipolar vs. exciton diffusion
• Excitonic and deep-level emission from N- and Al-polar homoepitaxial AlN grown by molecular beam epitaxy
• Composition and optical properties of (In,Ga)As nanowires grown by group-III-assisted molecular beam epitaxy