Bromine-methanol etching of semiconductor crystals $Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ with different selenium concentrations
The effect of the selenium concentration in the composition of the $Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ semiconductor crystals on their etching with a bromine-methanol solution was studied. A thermodynamic model is proposed to describe the degree of etching of $Cd_{1-x}Zn_{x}Te$ and $Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ crystals. A thermodynamic law is obtained for the first time to describe the change in the etching rate of $Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ crystals with different selenium concentrations. Experimental dependencies are constructed for etching trajectories and etching rates with 5% bromine-methanol solutions of $Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ crystal samples with nominal $x\sim 0.1$ and selenium concentrations of $y=0$, $y=0.02$, $y=0.06$, and $y=0.1$. The average etching rates were 24${μ}$m/min, 18${μ}$m/min, 15${μ}$m/min, and 13${μ}$m/min. The threshold effect of a strong decrease in the etching rate upon transition from ternary $Cd_{1-x}Zn_{x}Te$ to quaternary $Cd_{1-x}Zn_{x}Te_{1-y}Se_{y}$ crystals, associated with hardening of the crystal structure, is identify and theoretically explained. The obtained experimental data are in good agreement with the theoretical estimates and will be useful for choosing the optimal regimes of crystal treatment.