Quantum-Confined Stark Effect in Al_xGa_(1-x)As Quantum Wells
Abstract
The design of an 810 nm reflection modulator requires Al_xGa_(1-x)As quantum wells (QWs) having an Al mole fraction of approximately x=0.065. In samples we have grown, the multiple QW region, consisting of Al_xGa_(1-x)As QWs separated by Al_0.3Ga_0.7As barriers, is embedded inside the intrinsic region of a p-i-n diode. Room temperature photocurrent (PC) measurements show that for even small values of applied reverse bias, the lowest excitonic absorption, though Stark-shifted, is significantly broadened and weakened in oscillator strength. In an attempt to determine whether interface roughness is responsible for this behavior, we have grown two samples one --- at a low substrate temperature (T≈ 610^circ C) and one at a higher substrate temperature (T≈ 680^circ C). We assume that for the high temperature growth, the QW/barrier interfaces are smoother and that this will decrease the tendency for the quantum-confined states to broaden so quickly with applied bias. In this talk, we compare PC measurements from both samples and present our conclusions regarding the effects of growth temperature on interface roughness and the character of excitonic absorption.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1998
- Bibcode:
- 1998APS..MAR.S2710T