These lines of code help make a better looking plot that can be exported for a notebook or a publication.

plot(x,y2,'LineWidth',1.8); %make curve thicker than default
axis([3 35 0 34])
set(gca,'linewidth',1.7)  %make axis lines thicker than default
xlabel('wavelength') 
ylabel('intensity') 
set(gca,'FontSize',26) %make text bigger than default