PrimeNG checkbox not getting checked by default

I have an angular project in which I am using a PrimeNG checkbox component but there is an issue when I am trying to set the checkbox's default value to checked. I even tried binding [checked] property but I guess it is not known to p-checkbox.

HTML file

<p-checkbox name="checkboxName" [(ngModel)]="checked" 
binary="true" label="Perform Notifications"></p-checkbox>

Component file

export class XYZ{
checked: boolean = true;
}

When that gets loaded, I can see value of checked variable as 'true' below in HTML page but the checkbox is blank or unchecked.