Compensation in Ge-doped p-type Ga1−xAlx As grown by liquid phase epitaxy

Publisher Website
Google Scholar
Abstract
The effect of compensation on the pair spectra from Ge‐doped p‐type Ga0.60 Al0.40 As grown by liquid‐phase epitaxy under high‐purity He ambient is investigated. It is found that when the amount of compensation is high, pair transitions occur mainly via the deep GeAs acceptors at low excitation levels. The addition of oxygen (0.3–0.9 ppm) or H2 (11%) to the He ambient during growth reduces the compensation, with hydrogen found to be more effective than O2. For reduced compensation, pair transitions via the shallow acceptors due to residual C and Si are favored. The compensation is due to the presence of residual donors such as S whose concentration varies from wafer to wafer causing fluctuations in the relative intensities of pair transitions. Since strong pair transitions involving shallow acceptors reflect low concentration of compensating donors and thus improved conductivity in the p layers, the use of H2 in the He ambient gas during the growth of (GaAl)As double‐heterolaser structures should be advantageous.